98 matches were found
- Wednesday, October 03, 2001 #4754
Is there an "equivalancy" formula comparing the effectiveness of one newspaper and and a television commercial that appears "x" times for equal recall?
- The Media Guru Answers(Monday, October 08, 2001 ):
No standard formula. Once you set your units, you mught compare awareness or other measures. The right comparison should allow common budgets, not compare unit to unit.
- Friday, August 17, 2001 #4663
Love, love, love this site! I think you are providing a wonderful service. I read a recent question which as about an OTS formula (OTC?) I have never heard of this term. Would you tell me what the letters stand for? (I looked in your media terms section, and it is not there.) Thanks,
- The Media Guru Answers(Friday, August 17, 2001 ):
Thank you for your kind words.
"OTS" or "opportunities to see" is used differently by various practitioners. One meaning is equivalent to impressions, or the number of exposures of a campaign to individual members of the target demographic; a summing of the audiences of all the advertsing occasions of a campaign. In this sense, "average" is not an appropriate modifier. Others may use the phrase "average OTS" as we in the US use "average frequency."
The term OTS is not commonly used in the US, but is standard in the rest of the English speaking world.
- Wednesday, August 15, 2001 #4658
Could use some help framing questions for my agency relating to the effectiveness of a media campaign. We recently ran a test cell for a new campaign (our first)in which the agency provided information on total TRPs, total reach and total frequency over the life of the test. I need to determine how the frequency builds over time. Are there any formulas/rules of thumb for calculating build over time? If not, what specifically should I ask them for?
- The Media Guru Answers(Wednesday, August 15, 2001 ):
Reach relates to GRP in a curvilinear function. Frequency relates to GRP in a straight line. This doesn't mean that each week adds the same amount of frequency, merely that it's fairly easy to work with.
The easiest thing however, is probably to ask the agency to calculate cumulative reach and frequency, week by week, over the course of the campaign.
- Saturday, August 11, 2001 #4650
can you give me the formulae to calculate the OTS viv a vis competition in the print media.
- The Media Guru Answers(Saturday, August 11, 2001 ):
The question isn't quite clear: If you mean the formula to determine what your own OTC goalshould be vis-a-vis competition, it is very simple:
If Y= your goal OTS and
C = competitor's OTS then
Y > C
If you mean a formula to calculate your competitors current OTS, you need to have quantities from reports before you can determine what formulae to apply. For example, do you know spending ($)and average cost per OTS (O)? Then the formula is
$ ÷ OTS
- Monday, July 09, 2001 #4563
Increasing Budget and Web Response: Is there research showing that if I double (triple, whatever) an overall promotion budget to drive click-throughs on a Web site, I'll double--or more than double -- the rate? Is there a formula that can be presented to the client.
- The Media Guru Answers(Wednesday, July 11, 2001 ):
Like the reach curve, "response" functions are typically curvilinear, that is, once they reach a threshold level, each added dollar adds less return than the prior efforts.
As far as research that might yield a formula, try The Internet Advertising Bureau or The Advertising Research Foundation InfoCenter. For details about the InfoCenter, call 212-751-5656, extension 230.
- Friday, June 29, 2001 #4538
I have two questions about calculating reach and frequency that I have been unable to find in the archives of past responses. Perhaps you can help?
1. I normally use the formula (a+b)-(.a*b) to determine combined reach of two mediums, such as radio and print. How do I calculate the combined reach of more than two? The plan I am working on includes spot TV, spot radio and local newspaper.
2. Is it possible to determine a combined reach for more than one market or should each market be reported separately? In the past, I have provided separate delivery for each market in the same plan with a total number of gross impressions for the whole plan. Is this correct?
Thanks in advance!
- The Media Guru Answers(Friday, June 29, 2001 ):
1. This common formula is based on an assumption that different media duplicate their audiences according to random probability. Therefore if you follow this assumption, media may be added to combinations of media in a "chain" of the same formula. So, once you have combined TV and Radio, you can use this combination as your "a" and then combine it with newspaper as "b."
2. You can combine reaches across markets by doing a weighted average. Multiply the reach in each market by the percent of U.S. in each market. Add all the products and divide by the sum of the % U.S.
- Tuesday, May 08, 2001 #4379
Dear Media Guru:
Are there any "magic" formulas regarding advertising levels/weights and retail traffic pull through?
Please advise. Thank you.
- The Media Guru Answers(Tuesday, May 08, 2001 ):
There is no general magic. Individual experience will tell how it works in specific advertisers cases. There may be some ability to generalize within categories, as broad as "upscale restaurant in the NY metro area."
- Monday, May 07, 2001 #4375
Is there a formula or program for calculating
optimum daypart mix? I am working on a client that
has used the same daypart mix for years. I wanted to
really put some thought into this plan and not rehash
every previous years plan and thought there must be
some way to take the MRI information in comparison
to the CPP's for each daypart.Please advise. Thank you!
- The Media Guru Answers(Saturday, May 12, 2001 ):
This is the task of programs called "optimizers" of which so much has been written. AMIC's sister company, Telmar, offers one called "Transmit".
Also see writings about optimizers in AMICs Ephron on Media area.
- Tuesday, March 20, 2001 #4273
Can you guess at an estimated reach for a 4-week radio schedule at 150 TRP/WK (W2554)? Also, do you happen to know the formula for manually figuring reach/frequency?
Thanks for your help!
- The Media Guru Answers(Tuesday, March 20, 2001 ):
The formulas for radio reach are enormously complex and must take into account number of stations, daypart mix, average rating and other variables.
Your 600 GRP schedule might generate (roughly) from 35 to 70 reach, depending on these variables.
Click here to see past Guru
responses abourt calculating reach.
- Friday, February 23, 2001 #4202
We are doing the planning for an acount in a market we have not previously bought. The demo is Adults 25-54. What formula is used for establishing the weight distribution per daypart. If we are asked to buy 150 points per week how do we determine what the percent of each daypart.
- The Media Guru Answers(Sunday, February 25, 2001 ):
This depends on plan goals. If reach is the main goal, then you can examine a variety of mixes of weight to see the best reach available within the budget. The same technique works if the goal is effective reach or frequency.
In all likelihood, starting with about 20% - 25% in each of 4 or 5 dayparts and changing mixes in 5% increments, you will find very little difference except by adding or deleting prime time totally.
If impressions weight is the key, then just buy according to best efficiency, once your reach minimum, if any, has been met.
- Thursday, February 01, 2001 #4145
Is there a tool or a formula that can effectively guestimate the number of leads expected from an advertising campaign?
- The Media Guru Answers(Saturday, February 03, 2001 ):
The only valid tool is past experience with similar campaigns. In direct response the importance of the content (offer, price and pitch) means that media factors are outweighted as predictability issues.
- Saturday, January 27, 2001 #4129
I'm looking for information concerning Fair Share in television. Is there any other way to tell how much % one should invest in a television channel? Since the Fair Share formula is taking the amount of breaks one channel has into account, the more breaks a channel has the more % of the media budget will go to this channel. So even if a channel has let's say 30% of bad breaks (not viewed by the audience) this channel will score good in terms of Fair Share.
What's your opinion on this?
Thanks in advance!
- The Media Guru Answers(Sunday, January 28, 2001 ):
The Guru does not support buying based on stations' share of viewing. This practice undercuts the point of negotiation. If a station sales person thinks he/she is entitled to "X" share of your budget, then the incentive is to keep unit prices high.
It is even less logical to reward a station for having more inventory, which is a disincentive to viewing.
Share might be a starting point. Efficiency, reach/rating and composition should be essential adjuctments from there, and number of breaks of little or no impact.
- Wednesday, January 17, 2001 #4103
When was the last time the Reach & Frequency Curve was updated? And what is the significance of that?
- The Media Guru Answers(Wednesday, January 17, 2001 ):
Reach, as we use it, is a mathematical calculation, based on average performance of actual schedules similar to the ones for which we are trying to estimate audience accumulation for a plan. A large number of actual schedules are evaluated from survey research such as Nielsen. Because reach is a factor of duplication, as a schedule grow in size, the reach added by each increment is less and less. When reach is graphed against an axis of GRP or insertions or dollars, an asymptotic "curve" like the one below, is drawn. The actual formula which descibes this graphic curve is what is in reach evaluation software. Typically it is a regression of the frequencies vs GRP levels, because frequency, too, is linear.
The Guru imagines you are thinking of TV reach, but could be referring to radio, magazines, or internet, etc. There are different "curves" for any given medium / daypart / demographic / mix situation. If you use Nielsen actual data, the "curves" are -- in effect -- continuously updated. If you use other media software like Telmar or its competitors, you need to ask your representative how recent their update of formulae is. Curves based on reach vs GRP are not very variable over time unless there is a major change in the medium.
For example, Telemundo's Hispanic TV reach system "STRETCH2," was updated in 1998 (by running new Nielsen actual schedules), 5 years after its introduction . There was no significant change in reaches.
But looking at general TV reach curves from the days before cable was significant, versus today's would show big differences.
- Friday, January 12, 2001 #4096
How do I convert HH numbers into a Demo number. In some markets, my clients want me to post weekly to keep on top of shortfall, however, that's means using a HH number from the overnights. I need to see how that relates to the Demo. Can we just assign a HH and demo ranking going in and then check HH to HH - or can I use a formula to convert.
- The Media Guru Answers(Saturday, January 13, 2001 ):
There is no formula that works in the absence of data such as viewers per viewing household or demo audience in thousands. Lacking those, the Guru would take the average ratio of HH to demo audience by daypart, according to the latest available demographic data. Use these ratios as a factor to apply to the HH overnights for your tracking.
- Saturday, December 23, 2000 #4063
I am a very new media planner so I have a very basic question. What is the difference between average Frequency and average OTS and what is the formula for their calculation.
Thanking you in advace.
- The Media Guru Answers(Saturday, December 23, 2000 ):
"OTS" or "opportunities to see" is used differently by various practitioners. One meaning is equivalent to impressions, or the number of exposures of a campaign to individual members ot the target demographic; a summing of the audiences of all the advertsing occasions of a campaign. In this sense, "average" is not an appropriate modifier.
Average frequency is the average number of exposures experienced by the members of the target who have been exposed to the campaign (net reach) over a measured time period such as 4 weeks.
Gross impressions ÷ net reach
GRPs ÷ percent reach.
- Thursday, December 07, 2000 #4026
If there are 2 different target groups need to be sufficient in one TV schedule, the weight of rating for Target A is 40%, for Target B is 60%. how to calculate/evaluate the performance? and does it have a standard formula?
Thanks for your answer in advance.
- The Media Guru Answers(Friday, December 08, 2000 ):
If the Guru correctly understands your query, it seems like a simple weighted average would work.
- Thursday, December 07, 2000 #4025
What is the formula for cost per thousand?
- The Media Guru Answers(Thursday, December 07, 2000 ):
Cost ÷ impressions expressed in thousands.
- Tuesday, December 05, 2000 #4016
Hollow, Dear Guru! Can You help me please to clearify, is it possible to predict sales if we know expected advertising campaign effectivness? I mean can we somehow correlate pre-campaign analysys data with data we get from the client about the product? Is there any formulas and methods and what information about advertised product do I need?
- The Media Guru Answers(Wednesday, December 06, 2000 ):
A.C. Nielsens' BASES is a system for this sort of analysis.
- Thursday, November 09, 2000 #3958
What is the definition of dispersion and what is the formula? We are looking at various demos, their indexes across two programs to find out how stongly the shows are affiliated demographicaly. Is it a valid method to achieve such an objective.
- The Media Guru Answers(Sunday, November 12, 2000 ):
You haven't stated an objective. "Dispersion" refers to the degree of difference in media outlet selection in your schedule. In TV it ususally refers to the number of different programs, in radio to the number of different stations, but may mean different dayparts. The usual basis for specifiying dispersion is how the reach models were constructed.
- Wednesday, November 08, 2000 #3950
How is reach and frequency determined for a print (magazine) schedule?
- The Media Guru Answers(Sunday, November 12, 2000 ):
The average issue audience, measured duplication between issues of the same publication and between different publications are compiled using various formulas. Generally commercial media software like Telmar's or that of the magazine measurement vendors is used.
- Thursday, October 19, 2000 #3897
Dear Guru: My events department asked my how to estimate the "media value" of a product metion during the lead story of a primetime show like entertainment tonight. I told them that this was a very broad question, and it would vary depending on who the target was, what the ratings were, and what value really meant (i.e, dollars? contirbution to product sales? % contribution to frequency of a campaign, etc. They didn't know. Can you confirm how to go about this? What info do I really need? Am I on the right track? Do you have any math formulas to estimate this?
- The Media Guru Answers(Thursday, October 19, 2000 ):
Your thinking is exactly right. The Guru kows you as a regular and recognizes that you have followed his thinking from replies to past queries.
In terms of "media value" you would best stick to media metrics, like dollars, reach, frequency, etc. In considering dollars, you can relate the length of the metion --full context, not just brand name mention -- to price of commercials.
If thinking about impact, the Guru believes such a mention, is worth twice as much as advertising because of its implied indorsement. This of course assumes it's a positive mention, not something like "the strangler's weapon was a pair of Donna Karan pantyhose."
- Wednesday, August 30, 2000 #3767
Dear Guru, we are getting into awareness based media
planning which means objective will be set on awareness
scores, rather than GRP, R&F. Please tell me the
factors which are required and procedure for setting
awareness objectives.Thank you
- The Media Guru Answers(Friday, September 01, 2000 ):
Very theoretical. There is no specific rule of thumb equating awareness to GRP. There will be a big difference in saying the objective is to achieve 30% brand awareness versus increasing an existing awarness of 30% by 30 points.
You should think about:
- What percent of "aware" persons will be purchasers?
- What number of purchases is the pay-out level of your advertising?
- How often does the aware person make a purchase decision?
- Assuming awareness never exceeds reach, what reach must you acheive and what decay rate can your afford to maintain the awareness that will drive sales?
Frankly the Guru believes that saying "awareness based media planning" is just putting a marketing spin on the media plan. Ultimately a media plan sophisticated enought to have objectives almost invariably has some awareness objective mentioned. And ultimately, media must be bought in terms of GRP or impressions or insertions; the media vendors do not sell quantities of awareness. So either you have a formula which equates awareness numbers to media units or you do not. The Guru does not.
- Friday, August 25, 2000 #3747
can you please explain various tools through which one can determine the efficieny of a TV plan
- The Media Guru Answers(Monday, August 28, 2000 ):
"Efficiency" has a standard definition, so it is subject to arithmetic formulas rather than tools. Efficiency is defined as cost per unit of audience. "Audience" might be expressed as impressions or rating points.
So "efficiency" usually means, CPM (Cost per Thousand), which is the cost of a schedule or advertising unit ÷ the sum audiences of the ad units (in thousands) and CPP (Cost per Point) is the cost of a schedule or advertising units ÷ the sum of the ratingss of the ad units.
- Wednesday, August 23, 2000 #3737
I am trying to figure out the wearout for print. My target is African Americans 12-24 and 18-49. All I have is the FY reach, freg and TRPs. What would be my next steps?
- The Media Guru Answers(Monday, August 28, 2000 ):
There are no accepted standard formulas for wear-out. By the nature of print, which tends to yield high reach adn low frequency, there is generally less concern about wear-out than in broadcast.
Some of the broadcast rules-of-thumb for wear out include "over 20 frequency in the second highest quintile" or "2000 GRP.
Niether of these are likely to occur in print. Custom research may be the only real way to evaluate this. Start with Starch.
- Monday, August 21, 2000 #3728
What is the formula to equate reach and frequency from
an outdoor showing? i.e. a 25 showing has a reach of
76.8% and a frequency of8.2 (I pulled these numbers from
your media glossary)
- The Media Guru Answers(Monday, August 21, 2000 ):
"25 Showing" in out-of-home media indicates a buy with a daily effective circulation, or traffic count, or impressions, which equate to 25 GRP per day.
In considering a month's reach & frequency, it is common to adjust the weekend days' traffic down by about 50%. In a month, instead of 25 X 30 = 750 GRP, we credit about 630 GRP. This agrees with the arithmetic of 76.8 Reach and 8.2 Frequency.
- Friday, August 18, 2000 #3718
I am new in the field of internet advertising sales, and I have never sold ads for the media before. Are there any web based pricing charts or formulas to use for calculating conversion rates, cpm, cpc and cpa?
- The Media Guru Answers(Saturday, August 19, 2000 ):
Sample pricing and a cpm calculator can be found at Ad Resource.
"CP_" anything means "cost per" whatever. It's simply cost divided by thousands of ad impressions or clicks or anything.
- Wednesday, July 26, 2000 #3654
Please provide formula to manually calculate Reach & Frequency for press. Thanks
- The Media Guru Answers(Saturday, July 29, 2000 ):
This calculation is very complicated. If you don't have detailed tables of duplication factors between different publications and between various numbers of multiple issues of the same publication, only fairly crude formulae are available.
Click here to see past
Guru responses about reach calculation formulae.
- Thursday, July 13, 2000 #3618
On July 5 you responded to a question regarding the
decline of brand awareness due to reduced advertising
activity. You indicated that the "formula predicts that
a brand running low GRPs per week loses awareness and
a brand with no activity loses 5-10% of the previous
week's awareness each week." I would love to pass this
information along to some clients. Is there a source
I can quote?
- The Media Guru Answers(Thursday, July 13, 2000 ):
"5-10%" is a general summary of experience with various estimates the Guru has found over many years.
The Guru has been told that some people are quite comfortable citing the
"AMIC Media Guru, http://www.amic.com/guru/index.html"
as an information source.
It shouldn't need documentation to understand that awarenness will decline when there is no advertising. It also seems easy to assume that it will be like an inverse reach curve:
constantly approaching 0% in constantly decreasing increments.
No doubt many supporting studies are available through The Advertising Research Foundation InfoCenter. For details about the InfoCenter, call 212-751-5656, extension 230.
- Wednesday, July 05, 2000 #3598
lets assume that a company has been running a branding and image campaign for 12 months at 800points a month. If the company goes completely dark for 6 months what are the expected effects on awareness and branding. The negative effects of going dark at then end of a branding campaign have been taught to me during several courses I cannot remember nor find a formula or case study which proves this point. Where can I go to find statistics or case studies to support your answer. Thank you again for you help.
- The Media Guru Answers(Wednesday, July 05, 2000 ):
The Guru can consider this in terms of ad awareness, since brand awareness is subject to so many more outside factors.
Whatever the level of advertising, awareness can never be more than 100%. One very simple formula the Guru has seen predicts awareness as a high percentage the previous week's awareness plus a small percentage of the current week's GRPs.
As will be obvious, this formula predicts that a brand running low GRP per week loses awarness. A brand with no activity loses 5-10% of the previous week's awareness each week.
Of course this is all general. One classic case is the old Certs "two, two, two mints in one" copy which had good awareness as a "current commercial" ten years after it last aired.
- Thursday, March 16, 2000 #3326
I would like to know if there is any equation to calculate media mix reach?
- The Media Guru Answers(Thursday, March 16, 2000 ):
There are several, equivalent ways to express the arithmetic to combines media according to random probability, which has been found generally adequate for the purpose of multimedia combination.
Here's an easy one:
- Work with two reaches at a time
- Treat the reach of each medium as a decimal (50 reach is 0.5)
- Add reach of medium A and medium B
- Multiply reach of medium A by Reach of medium B
- Subtract the product of the multiplication from the sum of the addition
- Reach of medium A = 40, reach of medium B = 55
- 0.4 + 0.55 = 0.95
- 0.40 x 0.55 = 0.22
- 0.95 - 0.22 = 0.73
- Combined reach is 73
To add additional media, treat the combination as medium A and the next medium as B.
In some cases, a planner may have access to research which shows that an adjustment should be made for actual, measured, duplication between different media, rather than use the "random probability" formula above. In that case, more sophisticated reach calculating software packages, such as those from
Telmar allow you to make the calculation and build in known adjustments.
- Tuesday, March 07, 2000 #3291
Is there a formula which calculates effective reach and
frequency? I know that reach x frequency=grp's, but how
can I determine what the effective reach and frequency
would be for 100 grp's or 150 grp's?
- The Media Guru Answers(Friday, March 10, 2000 ):
Of course there's a formula, but it can be immensely complicated. In fact, media planners rarely, if ever, considered effective frequency before computers became a part of everyday reach and frequency calculation in the 70's.
Your "reach x frequency=grp's" is not a formula, but merely the arithmetical relationship of these quantities as they are defined.
GRPs are the convenient weights and mesures we use in media buying. They are simple statistical measurements, whereas reach and frequency are more complex statistical models In some cases, there are relatively simple reach formulae derived from compiling the actual, measured reaches of actual schedules with known GRPs.
The formula is non-linear.
To find the effective reach of a schedule, you first determine level of frequency to consider "effective" and then examine the frequency distribution of the schedule to see how many people have been reached that number of times The frequency distribution shows exactly how many people have been exposed to each integral number of announcements in a schedule.
The math is based on non-linear functions. For any given reach and GRP set, the frequency distribution can vary considerably depending on the media combined and the dayparts within the media.
- Thursday, March 02, 2000 #3274
What are the criteria that a media planner has to
consider when planning for advertising on the internet?
- The Media Guru Answers(Saturday, March 04, 2000 ):
The criteria are the same as in any media planning: reach, environment, composition, consumer response, etc.
In the internet there are merely different sources, standards, and formulas in dealing with these elements and thousands more options.
A couple of the most important differences are
- One "page" of a web site gets only a fraction of the audience of the total site, as compared to a page of a magazine, which is treated as if it had the same audience as the entire issue
- Audience ranking is much less relevant for the same reason: If Yahoo reaches half of all web users, but your banner is only exposed to one million of those unique visitors, how is that different than you banner being seen by one million uniques visitors to a web site which only gets one percent of all web users?
- Wednesday, February 23, 2000 #3239
I need to analyze a cpm tv negotiation on w1849.
I would like to transfer the negotiated w1849 cpm to w2549. Can you please explain the formula to transfer
- The Media Guru Answers(Thursday, February 24, 2000 ):
Step 1: calculate the vph ratio (or impressions ratio) of w25-49 versus w18-49.
Step 2: divide the w18-49 cpm by this ratio.
Suppose w18-49 CPM = $10.00
Suppose the w18-49 vph is .700 and w25-49 is .600
then the ratio is
.600 ÷ .700 or
Then $10.00 ÷ 0.857 = $11.66
It's best if you have the actual vph or impressions of your buy, but you can make an estimate from the daypart averages.
- Thursday, January 20, 2000 #3136
Is there a simplified reach and frequency calculation formula that allows for the number of stations (TV or radio) as well as the target audience size?
- The Media Guru Answers(Saturday, January 22, 2000 ):
Reach and frequency calculations have become quite complex today and are typically done by computer. Because reach is curvilinear, the formula can be quite complex, even without this issue. A different algorithm is needed for each dispersion scenario.
A good system will account for number of stations, at least in radio; AMIC's sister company, Telmar has such a system.
Since reach calculations are typically done with percentages of universe, like rating and percent reach, target audience size is not specifically relevant. Different curves will have been deduced for different targets, based on their accumulation patterns, which may not exhibit a direct correlataion to size. If reach in thousands is needed. it is simple to calculate by multiplying perent reach against target population.
- Wednesday, January 05, 2000 #3096
Oh Great Guru --
I need to calculate GRPs, but I don't have reach or frequency on some tv buys. I do have CPM, total impressions and impressions/week and the total population of the demographic. Can you supply a formula for calculating GRP based on what I have?
- The Media Guru Answers(Wednesday, January 05, 2000 ):
(Impressions divided by population) x 100 = GRP.
if impressions are 2 million and population is 1 million, GRPs = 200.
- Monday, December 20, 1999 #3061
Dear Media Guru, we are currently in the process of conducting a dip stick media survey to be integrated in a media reviews presentation for an FMCG. Based on your experience and references what would be the minimum acceptable sample size to use in order to insure the research findings are viable and reliable ? Note that the total population in our market is close to eighteen million, and the specified target group is about ten million. Thanks.
- The Media Guru Answers(Monday, December 20, 1999 ):
The population is not really relevant to determining the reliability of a sample.
The key consideration really is: what size are the answers you expect and what potential error can you stand in your decision making?
The formula to calculate one standard error (68% confidence) is:
The square root of ((P times Q)divided by N),
For 90% confidence, the above formula is multiplied by 1.645.
- P is the percentage of the sample offering the response to test (treated as a decimal fraction)
- Q is the remaining percentage of the sample, and
- N is the sample size
When you hear that results of a political poll are +/- 3%, this is the range of error around a 50% answer, usually at "90% confidence," meaning that if the poll was repeated with the same sample size, 90 times out of 100 the same question would have a response between 47 and 53%.
"+/-3%" on an answer of 50% means 6% relative error.
A sample size of 750 would bring you +/- 3% on a 50% answer:
100% - 50% = 50%
P=0.50, Q=0.50 and N= 750
0.50 x 0.50 = 0.25
0.25 / 750 = 0.000333333
Square root of 0.000333333 = 1.8275
1.8275 x 1.645 = 3.003
That's fine for political polls, where responses tend to hover around 50%. But in media studies, 1% or 2% may be exposed to a given ad placement. The same 750 sample would give reliability of +/- 0.84 on a 2% response, which is a relative error of 42%.
So, use this formula with your anticipated answer sizes and the level of relative error with which you can comfortably make decisions to determine a suitable sample size.
- Thursday, December 09, 1999 #3039
how can i estimate reach precentages?
is their any model that i can study from?
i ask you before about raech and you answered that its
a judgement decision.
i am trying to estimate how many people will wxposed once , twice, and more to my ads on t.v
( old brand, the first time to adverise , direct competitores are not using advertise at all
the largest share of voice, the target audience: main shopper with children )
is it enough to compare my case to other t.v campaign
which had some close goals( target, budgets, adverisment environment, and so on) or may you
has any other way to guide me?
please try to help me
- The Media Guru Answers(Thursday, December 09, 1999 ):
There are many parameters to consider for various media and dayparts. Computer models seem to be the only sensible way to deal with all of today's options. AMIC's sister company, Telmar, which has offices in your country (Israel), is the leading worldwide provider of this type of software.
Statistical texts can give you information about some of the basic reach estimating formulas, such as the Beta Bi-modal function.
- Tuesday, December 07, 1999 #3033
Without the budget for post-flight call out surveys what formulas or 'rules' can I use to anticipate message saturation and burn. What reach or net reach level over what period of time would be probable to achieve a 80% awareness within the target. Also what is considered too much exposure for one message before you reach a point of diminishing returns. I know that the the better measurment here is research before and during the campaign, but there must be some bench marks that are industry accepted. Can you share these and share a public location for other general assumptions like this. Thank you in advance Guru...
- The Media Guru Answers(Wednesday, December 08, 1999 ):
Ad awareness will never be greater than reach, so start from a plan that delivers at least 80% reach
- To establish measurable awareness, some repetiton will be needed, so think about getting an 80% reach at a set effective frequency level. The Guru has previously discussed use of the Ostrow Model to set this goal.
- A message is worn out when its ability to generate sales falls off. This being hard to predict, many advertisers have used past experience to set media-measurement based cut-offs. These have included a limit of 2000 GRPs and a frequency cap of 20 in the second highest quintile. In reality, the size of the copy pool, the qualities of the copy, the target, the overall media mix, and product category may all lead to wide variations in wear out. The two standards mentioned above were both commonly used in basic package goods TV advertising in a mix with print and a TV copy pool of 2-3 executions.
- Thursday, November 18, 1999 #2984
what advertising agents do,how they do it,modes of renumeration and types of advertising agencies
- The Media Guru Answers(Sunday, November 28, 1999 ):
Most basically, advertising agencies create and place advertising in the media. Agencies also participate in and herlp guide marketing planning. The services are traditionally compensated by 15% commission on gross media bought and 17.65% on net production or other out of pocket expenditures - 15% of gross and 17.65% of net are actually identical proportions.
Some agencies specialize in product categories and others may specialize in specific consumer categories, like medical professionals. Other specialize in media like on-line.
Compensation deals are most likley to vary from the 15% formula for very large or very small accounts.
- Friday, November 05, 1999 #2938
I'm hoping develop a reach curve for a client to shhow how audience accumuluates with increased dollar spending in the market. I have a table that shows % reached by GRPs per 4 weeks and wondered where I could get published tables and surveys realting to increased share of voice in realtion to share of market spending. Is there are projection formula that could be used?
- The Media Guru Answers(Wednesday, November 10, 1999 ):
Share of voice usually means share of GRPs. Developing a Cost Per GRP index would give you a simple conversion. The shortcoming of share of voice is that it ignores impact differences between various media and copy units, unless comlex formulae to equate GRPs are created.
- Tuesday, November 02, 1999 #2928
I'm trying to plan an online media buy for branding purposes and having a hard time devising a formula for adequate impressions levels. I think % reach is a better way to go, but what's the optimal % reach for online branding on a website (high enough frequency without waste)? Thanks!
- The Media Guru Answers(Wednesday, November 03, 1999 ):
It is very early in the scheme of internet reach models to imagine that there are standardized formulas.
You are correct to think that "branding," which means different things to different people, but seems to be about awareness in most definitions, depends upon reach.
But reach in relation to internet impressions is a curious thing. As in all media, it depends upon duplication between one day's visitors and the next plus duplication between one site's visitors and another site's.
When reach formulas are created, they begin from examination of the actual reach and frequency in real advertisers' schedules.
In this connection, it is instructive to visit the "Top 10 Advertisers of the Month" page at Nielsen//Netratings, a web audience research firm. In the month of September, 1999, the #1 advertiser, in terms of impressions, was TRUSTe, with 945 million immpressions and 25% reach among persons with internet access. But Amazon.com, the advertiser with the highest
reach, at 44%, had less than one-third as many impressions, 273 million. Other advertisers with as few as 103 million impressions surpassed TRUSTe's reach.
The bottom line is that
- Clearly, there is not a lot of consumer reach possible on the web, if the top advertisers' perform like this.
- Impressions-to-reach models are going to be complicated to build.
- We probably need a new definition of "branding" for on-line purposes.
- Saturday, October 30, 1999 #2921
How do we compare national TV-sponsorship in terms of cpm, with traditional spot buying?
In order to do this we need to evaluate the lenght, creative factor and the added value of presenting the program. I have used formulas including these factors using indeces. Is this the "right" way of doing it? Do you have these formulas, indeces?
- The Media Guru Answers(Monday, November 01, 1999 ):
Most of the comparison should be purely and simply cost-based.
Length and creative would not be a part of the difference between national and spot. The same commercial can run in either environment.
If you literally mean national sponsorship, that is with Opening and/or Closing billboards, this can be quantified by added length. As for formulas and indices, if you get ten "free" seconds of airtime, it is worth one-third of what you paid for a thirty. Any other element of national vs local is purely a matter of price and geography. Allowing a value for "in-program" positions versus in-break would be a judgement call and not worth much, in the Guru's opinion.
- Wednesday, October 20, 1999 #2892
I am attempting to do a publicty report for the coverage (unpaid) our organization receives on a quarterly basis. I have been calculating the advertising value of publicity, based on what each medium would typically charge for that size ad. However, I am looking for a formula to calculate the publicity value of such coverage. I understand that the National PRSA has come up with a formula to calculate this (something like X 3 for television and X 6 for print), but I haven't been able to substantiate this. Can you help?
- The Media Guru Answers(Wednesday, October 20, 1999 ):
The Guru doesn't deal with publicity, but if PRSA has a standard, the advantage is that it is a standard.
- Thursday, September 30, 1999 #2838
Useing TV's formula for ratings, apply to the newspapers circulation of 108,000 with a population of adults 289,400. What would be a rating number for this situation?
- The Media Guru Answers(Friday, October 01, 1999 ):
If we know that the circulation is 108,000, we next need to consider the readers-per-copy to get your answer. According to the The Newspaper Advertising Association the 1999 daily newspaper's average adult readers-per-copy is 2.148. Therefore, your 108,000 circulation would have 108,000 x 2.148 or 231,984 readers.
With an adult population of 289,400, the rating would be 231,984 ÷ 289,400 or 80.2, which indicates a very popular newspaper, indded.
- Monday, September 27, 1999 #2830
I have read all your responses regarding recency. If you wouldn’t mind answering a few more, this is a multiple question predominantly regarding recency as a planning theory.
1) What Telemar program deals with TV R&F on a weekly basis?
2) Do the same audience accumulation formulas work for a one-week cume vs. 4wk or 52 wk?
3) When now planning an a weekly basis rather than a flighted basis are frequency guidelines or goals a consideration in the recency planning theory?
4) Has there been a clear industry swing relative to EF or recency yet?
5) A 1997 JAR article by Erwin Ephron cited some minimum target reach guidelines like 35 weekly, 65 four-week and 80 quarterly. Has there been anything more definitively determined since then (I noticed reply 2631 7/14/99 lowering the weekly reach to 30)?
6) For those espousing recency, is the trend to a 52 presence or extended flighting like 8-10 continuous weeks of each quarter?
7) On the Effective Frequency side, where the defacto goal has centered around the 3+ level, has the time frame shifted to anything other than a 4-week period?
- The Media Guru Answers(Wednesday, September 29, 1999 ):
1) Media Maestro and TV Buyer handle TV R&F.
2) No, formulas differ for one week, 4 week, and long term. 400 GRP, spread ove differend programs might come close to exhausting the reach potential of one week's TV audience, but not if spread over 4 weeks or longer.
3) Recency planning is focused on weekly reach, and incorporates the concept that every exposure after the third one is at the 3+ level.
4) Some have adopted recency, some cling to effective reach. The Guru is not aware of any polls of agencies or advertisers, but suspects that recency is still growing in acceptance, but is a minority approach.
5) The reach minima are a bit loose, and 30 vs 35 is not a major point of contention.
6) The idea of recency is that being there whenever a purchase decision is made is ideal. Flighting, when continuity is affordable and there is no major seasonality is contrary to the principle.
7) Four weeks has always been somewhat arbitrary, likley stemming from the one-time dominance of monthly magazines. But it is a convenient benchmark. A logical approach can set a level other than 3+ or other than 4 weeks, etc.
- Wednesday, September 22, 1999 #2815
Can you please refresh my memory and tell me how to
calculate multi-week reach and frequency across television
and radio? Thank you
- The Media Guru Answers(Thursday, September 23, 1999 ):
If you mean combining these media, the formula has been addressed. Click here to see past Guru responses.
If you mean how to get multiweek reaches for either medium, you need reach curves or software, the extension formulae are tow complex for casual use.
- Tuesday, September 14, 1999 #2795
I am writing to you from the Middle East. First of all I am very excited to discover the AMIC site.
I have recently been exposed to various documentation on the recency theory. Alongwith the documentation I have seen something called reach curves. The reach curves I have seen are typically for 1+, 2+, and 3+ levels for all adults and all women audiences. I understand it is an easy way to translate Effective Reach goals into GRP goals e.g. X GRPs will get you Y% 3+ reach against the target. It also clearly depicts the point of diminishing return.
I am eager to know how I can develop reach curves for my market. Can this be done by us in the media department or do we need to approach some company which specializes in this area. What sort of data is required? Just to give you a background, we are not a metered market. TV audience measurement is conducted thrice a year using face-to-face interviews with a representative sample. Viewership is typically available by 15 minute time segments for all channels across various demos.
Thanks in advance.
- The Media Guru Answers(Tuesday, September 14, 1999 ):
Reach curves have been in use since long before computers were used in media departments and long before metered measurement.
Curves are created by using the reach of actual schedules. For example, in the U.S., Nielsen would report the actual reach of specific brands' schedules, based on examining the net unduplicated viewers in their reasearch data who viewed the program schedules used by the brand's commercials.
Once you have several schedules ( 8 or so will do) with actual reaches and frequencies for various GRP levels, you can use the regression analysis data function in a spreadsheet, like MS Excel or Lotus 1-2-3, to calculate a formula which describes the curve. This formula can literally draw the curve on a graph, or let you build a table of GRP / Reach pairs. By the way, it is the frequency and GRPs which are used in building this regression, because while reach is a curve, frequency is a straight line.
- Tuesday, September 14, 1999 #2792
What can you tell me about reach-based planning?
Thank you in advance.
- The Media Guru Answers(Tuesday, September 14, 1999 ):
The usual assumption is that print and broadcast duplicate with random probability, there is no special, greater or lesser likelihood that persons in the audience of the print schedule will also be or not be in the audience of the broadcast schedule.
Mechanically. the combination may be calculated in a few equivalent ways. The Guru finds it easiest to consider the reaches as decimals (50% reach = 0.50).
Subtract the reach of print from 1 and multiply this by 1minus the reach of broadcast. Suppose print has a 40% reach and broadcast has 55%.
By subtracting 0.4 from 1 (1 - 0.4 = 0.6), you have the probabilty of the target not being exposed to print. Subtract 0.55 from 1 to get the probability of not being exposed to broadcast (1 - 0.55 = 0.45)
Multiply these two together (0.6 * 0.45 = 0.27) and you have determined there is a 27% probability of people not being exposed to either of the combined media, or a 73% reach.
This formula is typically used in media software to combine different media.
Certainly there are cases where there is a somewhat better than random probabilty of media duplication, such as TV Guide combining with a TV schedule, but that's the exception, calling for judgement.
- Wednesday, September 01, 1999 #2759
Is the random probability formula used to combine reach for different media also valid when looking at effective reach (i.e. 4+ level)?
- The Media Guru Answers(Thursday, September 02, 1999 ):
If you mean, can you combine the 4+ reach of one medium with the 4+ reach of another medium to get the 4+ reach of the two combined media, the answer is no.
Among those who were reached 2 or 3 times by each medium, some will now be reached 4 or more times and some will not, yet these people are not considered by combining only the two four+ groups. There are also those reached only once by the first medium and three times by the other, etc. A new, overall calculation of the frequency distribution must be done, to determine the 4+ of the combination.
- Thursday, August 19, 1999 #2729
1- Please let me know SQARE model that SQAD use to calculate CPP for TV and Radio. Please let me know the detail or any link I can find more information or books...
2- Do you know any model for reach vs GRPs? Our client ask us to show the data like that. The problem that we try to find the suitable daypart mix, station mix, medium mix that is good for our advertising strategy but we don't have any optimiser programs. We have only ratings data like Telescope and Prinscope of ACNielsen. Do you know any example to solve this kind of problem?
3- Our client also want to have a model to set advertising budget to get for example 80+ reach but we can not know until it happen. How to solve this issue?
- The Media Guru Answers(Thursday, August 19, 1999 ):
A general explanation of SQAD's model is available from SQAD. They will give you the same information they would give the Guru. But the essence is manipulating actual buying data in real situations, provided confidentially by actual media buyers.
GRP's and reach do not have any standard realtionship, except within given media and population parameters. You are writing from Viet Nam, where Televison audience cume patterns are likely to be quite different than in the U.S. Even within the U.S., Hispanic TV reach curves are very, very differerent than the General Market TV reach curves.
The way to build a model, to oversimplify, is to collect a great number of actual reaches of real schedules, and then plot their frequency against reach in a regresssion analysis, which gives you the formula for the "curve." Frequency is plotted, rather than reach, because frequency is a straight line while reach is a curve. The curve formula then allows you to create a model with a reach solution for any GRP input. The more variables you use to build different curves, the more sophisticated your model can be.
- Thursday, August 19, 1999 #2727
The formula for calculating the reach of media vehicles is (a+b)-a*b.
Please tell me the "N" formula for it,
or you have a different formula for calculating reach?
- The Media Guru Answers(Saturday, August 21, 1999 ):
Your formula is for " random probabilty," which is used to combine two different media, based on the assumption that their audience duplication is purely at random. This formula is not appropriate to combining different vehicles in the same medium, which typically have more than merely random duplication.
There are various, quite complex formulae for computing reach of various vehicles of the same medium, among them the Beta Binomial, Lamda function, and others. The Guru is not familiar with your reference to "the 'N' formula."
- Tuesday, July 20, 1999 #2649
Could you please explain the formula for calculating median age for a TV Network based on AA(000). Also would looking at the Median age based on Reach(000), make sense.
- The Media Guru Answers(Friday, July 23, 1999 ):
The median of anything is the number that falls in the middle when everything is arranged in order. So to find median age, ideally you need to find out how many viewers are two years old, how many are three, etc up to 99+. If you can't get it by single year, get the smallest brackets possible. Then you find the age which has an equal number of people older than that agaand an equal number younger, this is the median age. If you are working with age goups instead of single years, you may have to assume that the median is the mid-point of the median age group, weighted according to the number older and younger.
For example, suppose there are 10 million viewers, and there are:
2 million age 2-11 years
2 million 12-17
3 million 18-24
1 million 25-34
1 million 35-49
1 million 50+.
With 10 million viewers you need to find the person who has 5 million people older than he or she in the audience and 5 million younger.
This person must be somewhere in the 18-24 group, because we can tell there are 4 million younger than this group and 3 million older.
Rather than just pick the mid-point of 18-24, you should interpolate according to the other numbers: the mid-point age should be 4/7 along the span 18-24, toward the younger end, or 20 years old.
What would the median age of the reach do for you? It's dependent on the viewing frequency of the network which may not correspond to the ad placements of your schedule.
- Monday, July 12, 1999 #2623
Reciently I have read a couple of documents
that explain that you may estimate wearout using an
equation(applying quintyl analysis). I would like to
know if there is any equation to estimate hoe many
grp's per version you need to generate awareness.
As always thansk in advance.
- The Media Guru Answers(Monday, July 12, 1999 ):
Any number of GRPs generate some awareness. So the question is how much aweareness do you want to achieve. Reach may tie more closely to awareness generation, but GRPs are easier to work with.
Also, consider whether you really care about awarness of individual commercial versions as opposed to advertising overall.
formulas the Guru has seen generally assume some beginning level of awareness and a fall-off in any week with less than100 GRP.
- Monday, May 10, 1999 #2496
what are the various terminology used in electronic media & their various formulas?
- The Media Guru Answers(Monday, May 10, 1999 ):
There are far too many terms to decribe here. See the Media Guru's Encyclopedia of Media Terms.
formulas for most have been provided in Guru answers from time to time. When you find one for which you need the formula, go to the Guru Archives Search Engine. Use the media term plus the word "formula" as your search terms.
- Friday, April 30, 1999 #2481
Is there any way to calculate duplication across a media plan using several media (e.g. print and radio and TV), or can I only get a duplication analysis within a media (radio duplicaton and then another duplication factor for print, etc , etc)
I use telmar for research with simmons and arbitron access and we also use JDS for buys.
- The Media Guru Answers(Friday, April 30, 1999 ):
The standard assumption in media planning is that duplication between different media is purely at random. Therefore, the random probability formula is used:
- Express the reach of each medium as a decimal (50% reach = 0.5)
- Multiply the reach of one medium by another to determine the duplication.
- Subtract the duplication from the sum of the two reaches to get the net reach
So, if you have a 40% reach in TV and a 55% reach in Print, multiply
0.4 x 0.55 to get 0.22
subtract 0.22 from 0.4+.55 and get 0.73 or
73% reach of the combined media.
There are a variety of ways to do the calculation. The Guru actually prefers to use the probablilty of not seeing each medium (reach as a decimal subtracted from 1.0) When these are multiplied they give the net probability of not seeing any of the media. When this result is subtracted from 1, the final result is net reach. This style is particulary useful for combining several media at once.The example would combine this way:
- 1-0.4 = 0.6
- 1-0.55 = 0.45
- 0.6 x 0.45 = 0.27
- 1-0.27 = 0.73 or
Telmar's "Media Mix" program uses these assumptions.
- Tuesday, March 23, 1999 #2403
I have been researching these questions for a number
of days now and have been unsatisfied with the
answers I have been receiving. I am a new member
and new to this field, any direction would be most
helpful. Thank you in advance...
1) What is the difference between Rate Base (a number
guaranteed by publishers and audited by ABC) and
Readership (a number provided by, say, MRI) levels
for magazine publications?
2) Which number (above) is most often used to
calculate CPM (I believe this calculation is
3) Is 'readership' really a composite number (perhaps
a result of some other formula)? If so, does
Page Exposure Rates factor into 'readership'?
- The Media Guru Answers(Tuesday, March 23, 1999 ):
If you went to AMIC's Rates, Dates and Data area and clicked the link
"Audience data from MRI is available for
Fall 1998 for Total Audience, Circulation and Readers Per Copy " you would see the table from which this image is taken:
The following discussion will use this table as a visual aid.
"Rate base" refers to circulation, the actual number of copies of a publication printed and sold for the average issue over a specified period of time. In the table, "Circulation" is the middle column of data.
"Readership" is the number of readers of the average issue. It includes "passalong" readers, who may not be the buyers / subscribers but read some else's copy. In almost every case, total readership will be greater than circulation. The first three columns of the MRI table we are looking at are readership numbers.
CPM can be calculated based on either circulation or readership. The circulation CPM (Cost Per Thousand) calculation is: divide ad cost by the number of copies in circulation.
The readership cpm calculation is: Divide ad cost by number of readers of an average issue. Often readers within a specified demographic the advertiser is targeting are the divisor in this second calculation. As a planning tool, the readership CPM is more common than the circulation CPM, especially for categories of print that use readership research, such as MRI.
Many people misinterpret the common reporting of "readers per copy." The last three columns of the MRI data are readers per copy figures. What audience research actually measures is readership. A random sample of consumers is interviewed and asked about their magazine reading to determine how many readers there are for an average issue of a magazine. Readers per copy is a calculation done after the fact, dividing the readers measured by the circulation. It is a handy factor used to compare magazine pass-alongs or to calculate other audience elements.
- Friday, March 19, 1999 #2400
I need to know the calculation to work out margin of error for TV reach and frequency results. E.g. what is the margin of error of 40% @ 2+ depending on the size of the sample, penetration etc.
- The Media Guru Answers(Saturday, March 20, 1999 ):
Assuming you are using a model to calculate reach and frequency, your error is no longer an aspect of sample size but of the reliability of the model.
For instance, suppose your schedule consisted of 20 advertisements with an average rating of 10. And, based on sample size, the 10 rating was +/- 2 rating points (or 20% relative error). But your total schedule of 200 GRP is not going to be +/- 40 points. Because error is plus or minus, there is an equal chance that one 10 rating is really PLUS 2 and the next 10 rating is really MINUS 2. So, in a schedule, most of the error cancels out. This is one reason why ratings minima for buying are often short-sighted.
When it comes to reach analysis, someone might have built a model by compiling several actual schedules measured by the original research and finding a formula for the straight line formed by the average frequency of each. Since the actual schedules came from the orignal research, the sampling error of each (minimized by the plus or minus aspect of the schedule elements, as above) could have been calculated. But now the "curve" coming out of the model is only judged by its ability to match back to actual schedules.
- Thursday, March 11, 1999 #2384
Dear Media Guru
Suddenly without my Strata software...what was the formula I learned so long ago for calculating Gross Rating Points?
- The Media Guru Answers(Friday, March 12, 1999 ):
The Guru has discussed this frequently.
Click here to see past Guru responses on
GRP and calculations.
- Wednesday, March 10, 1999 #2382
RE: My earlier question #2379, my boss responded this way: Pre-launch was a 2-week period, so an average 4-week number would have been
a misrepresentation of reality. If you do not have a 4-wk period for comparison than you should not do a
4-week r/f. Do you agree with this? How should I handle this disagreement with my supervisor?
- The Media Guru Answers(Wednesday, March 10, 1999 ):
The Guru disagrees. The phrase "average four week" in the context of Reach & Frequency refers to a rate of accumulation, not really the period of time other than the time periods actually measured in the original establishment of reach calculations. Four weeks was originally chosen as the basis for the actual measurements that built the formulae when monthly media (magazines) were the predominant national advertising media. One does not really care how much time is involved.
For marketing purposes, what is important is that you communicated an advertising message to X% of consumers an average of Y times. It is easy enough to say that "over two weeks, we reached 60% of the target an average of 3.9 times." No one is misled, nothing is invalid. You just happened to use a four week formula to determine the results. As the Guru said earlier. only in some 1-week cases will there be any real differerence. (As there would for long term cumes, like 13 week).
If your supervisor's only alternative is to report nothing, as if there was no way to measure the schedule, that doesn't seem productive.
- Monday, March 08, 1999 #2378
How do you figure out average four week r/fs without software?
Thanks for your help.
- The Media Guru Answers(Monday, March 08, 1999 ):
Before software, there were tables to get reach from broadcast GRP, and books of factors and formulae for print.
Those old tables are probably no longer valid, perhaps someone has done some new ones. The Guru has discussed this frequently.
Click here to see past Guru responses on
reach and frequency
- Monday, March 01, 1999 #2363
We found a formula that is supposed to calculate newspaper impressions. (insertion X circulation*2.28*0.58)/1000) We thought that this was calculated simply by multiplying the circ by the # of insertions. Do you know what this formula could be doing? Thanks
- The Media Guru Answers(Monday, March 01, 1999 ):
The Guru believes this formula is meant to estimate persons impressions. "Circulation" represents just copies, not readers.
The 2.28 factor looks like the Sunday average adult readers per copy. The 0.58 then would seem to be the composition for some demographic group, perhaps 18-49. The "/1000" seem to be meant to set the decimal for the particular context in which you found the formula, it will cause the result to be expressed in thousands. Perhaps the number of impressions derived from this formula was going to be used to calculate cpm.
See The Newspaper Advertising Association research databank. for other readers-per-copy and demographic composition data
- Tuesday, February 02, 1999 #2303
I am working on a BPA/ABC circ analysis for 2 trade publications. One is BPA audited and the other ABC audited.
On an apples to apples basis, how would I go about calculating a renewal analysis of average qualified subs for the BPA audited pub?
I.E. The ABC audited pub calculates the renewal rate accordingly:
Total Qualified Circ 1000
One Yr Total Subs Deleted* 200
Annual % not Renewed 200/1000 = 20%
Annual % Renewed 800/1000 = 80%
*Can this formula be applied to calculate renewal % for a BPA audited pub? I question whether we can integrate the "one year total subs deleted" figure as part of the equation.
- The Media Guru Answers(Thursday, February 04, 1999 ):
If the same data is reported on the same basis, comparison is fair. If comparable data is not reported, perhaps this is not a crucial analysis. The Guru believes this sort of analysis is likley to be a last-chance tie-breaker at best.
- Tuesday, January 26, 1999 #2289
Is there a formula that radio stations use to determine
the rate an advertising agency or buying service must
pay for advertising?
Also, would you know what the Total HH Universe
for Radio in America is , or where can I find
- The Media Guru Answers(Tuesday, January 26, 1999 ):
In setting rates, of course a station must cover its costs of operation. But radio is a negotiable medium and the station has to consider what the marketplace pricing (cost per point) is for the demographics in which they have strength or wish to sell.
The U.S. Household universe for radio is the total household universe, or roughly 100 million. But, because radio is a highly personal medium, and audiences are based on individual listening, households are not considered relevant for radio. Radio ratings for households haven't been provided in standard research for 30 years or more.
- Tuesday, January 19, 1999 #2276
What you can tell me about GRP and CPT? How to explain the formulas of them?
- The Media Guru Answers(Tuesday, January 19, 1999 ):
The Guru assumes that by CPT, you mean "Cost per Thousand," which is abbreviated "CPM" in the U.S., (using the Roman numeral "M" for one thousand)>
GRP stands for "Gross Rating Points." It is the sum of all the ratings of all the advertisements of a schedule. Or it is the sum of all the impressions of a schedule divided by the population of the geographic market under consideration. "Impressions" and "Population" must be in the same demographic category within the same geography when applying this formula.
CPT, or cost per thousand, is simple a matter of dividing the cost of media by the number of impressions delivered expressed in thousands.
- Tuesday, December 22, 1998 #2232
We use a buying service for our media. I'm just
learning and was asked what seems a simple question,
but do I have all the elements and could you
help me to formulate the equation to learn.
We are running 125 TRP's weekly in radio flighted
thoughout the year. 3,000 total TRP's for the year.
$550,000 total budget. CPP ranges from $32 to $200,
average is $90.
Q. With 125 TRP's a week, approximately how many spots
a week will this schedule produce?
- The Media Guru Answers(Wednesday, December 23, 1998 ):
The Guru assumes you are running 125 GRP in each market.
Depending on market and demographic, average ratings run from about 1.0 - 2.0 on top stations. Divide GRP by the average rating you will buy to estimate number of spots. At an average rating of 1.0, 125 GRPs represents 125 spots.
And you didn't need any of that cost or cpp data.
- Monday, December 21, 1998 #2230
I am currently analyzing a media schedule that includes consumer print, trade print and national cable. I have been
asked to pull a reach and frequency for the entire schedule. I realize that I am working with several differenct universes. I have added
the circulations and pulled the gross impressions for cable. I have added those together. Is there any formular to determan a reach and frequency?
- The Media Guru Answers(Thursday, December 24, 1998 ):
In general, different media have different audience accumulation patterns when thinking about net unduplicated audience vs gross audience.
Calculating reach from a total multimedia impressions number is not practical unless the gross rating points (impressions divided by GRPs) is so many thousands that a 95+ reach can be assumed.
Some media, in particular broadcast media, allow general estimation of reach from a table of GRP levels. Print media are more complicated.
What you really need is standardized media software for reach and frequency calculation like that which is offered by AMIC 's sister company, Telmar.
- Wednesday, December 02, 1998 #2193
We were asked to prepare a presentation for one of our clients about media planning,
since he works with several agencies and wants to concentrate
the media planning in one of the agencies' hands.
I visited the "parts of a Media Plan" which I found very helpful. Do you have some
Specifically, we were asked to present a formula for a
benchmark acocrding to we recommend to define what reach
is needed for a campaign. Basically, we define it according to
various factors such as competitors' share of voice, share of
market goals etc. but we don't know any formula.
We should be grateful if you supply any guidelined in this matter.
- The Media Guru Answers(Wednesday, December 02, 1998 ):
You just need to formularize the thinking you are already doing.
For example, you could say that your formula to set reach for a campaign to equal competitor's share is:
Competitor's Reach times an index calculated by comparing the goal share to your current share. (i.e. to increase share 25%, exceed competitor's reach by 25%).
The Guru is not recommneding this particular formula, just illustrating how to turn philosophy into something apparently quantifiable.
Another approach is to build a matrix of your factors and set a 5 point scale for each; for example competitor's share: 0 point if it's equal to yours 1 point if it's 10% better, 5 points if it's 50% better, etc.
Suppose you have 8 factors based on the sort of considerations you mentioned. Suppose further that you set a minumum for all campaigns of 50 reach (reaching the majority of the target). Now add a reach point for every point in the matrix. You have a maximum of 40 added points (90 reach), and an apparently highly logical "formula" for getting there.
The cleverness will be in setting up each 5 point scale. Or perhaps youy will have fewer factore and more possible point on each scale.
- Monday, November 30, 1998 #2179
How do you manually work out reach and frequency for TV campaigns. Is there a particular formula?
- The Media Guru Answers(Monday, November 30, 1998 ):
See the query of
Tuesday, November 10, 1998 #2144.
It is not feasible to do manual calcuations without tables, which are probably not being created any longer. Someone with the computer reach and frequency tool could develop the tables easily, but there would be little point.
Once reach has been determined for a range of possible schedules by various available means, there would be a fairly simple algebraic formula that describes the "curve." But, today, that's the long way around.
- Thursday, October 22, 1998 #2107
WHAT IS CHANNEL BUNDLING? ON WHAT PRINCIPLES IS IT BASED & UNDER WHAT CIRCUMSTANCES IS IT FEASABLE TO TO formulaTE THIS STRATEGY?
- The Media Guru Answers(Friday, October 23, 1998 ):
First, please do not send queries in all-upper-case.
Second, in regard to channel bundling, the Guru doesn't recognize this as a standard term. It may refer to buying/selling several cable networks under one ownership or representation.
Since cable ratings of individual channels are typically low, channel bundling can give a semblance of a bigger medium. As an nattempt at old-fashioned "roadblocking" it will fall short.
- Thursday, September 17, 1998 #2047
what is crr?
- The Media Guru Answers(Thursday, September 17, 1998 ):
The Guru is not familiar with this term. At a guess, it refers to cost per _____ rating. It may be a non-U.S. term the Guru has not encountered or it may be one companies own invented term from a system or formula of their own invention, similar to "persuasion rating point," which is discussed below.
- Tuesday, September 08, 1998 #2031
I'm new in the Advertising field. I would like to know
how to calculate the Target Market Reach1+, Reach2+,
abd the Average Frequency.
- The Media Guru Answers(Wednesday, September 09, 1998 ):
The answer depends upon what data you are starting with. At its most simple,
"1+" reach is the same as just saying "reach". If you know the GRPs, and the reach, then the average frequency is calculated by dividing reach into GRPs.
At bottom however, in each medium, TV, radio, print, etc. reach was actually measured at some point, rather than calculated . That is, using respondent level measurement, such as Nielsen or MRI or Simmons, actual schedules advertiser were evaluated for gross audience accumulated and the net reach accumulated, as well as how many people saw exactly one advertisement in the schedule, how many saw 2, how many saw three, and so on. As the Guru stated above, reach is defined as those who saw one or more (1+) advertisements. 2+ or 3+, etc, is determined by adding those exposed to each discreet number of ads.
Taking the results of many of these schedules as a scatter graph, a classic reach curve may be plotted. Or, by arraying GRPs and frequencies in a table, a formula equivalent to the curve can be determined statistically. This formula then becomes a "model" for calculating reaches of other schedules in similar media. formulae for 2+, 3+ frequencies can also be calculated. There are no simple formulas for doing this. "Beta Bimodal" is one statistical function frquently used. These functions and models are usually built into large computer media planning systems like Telmar's.
- Friday, September 04, 1998 #2028
I am currently pulling together information for one of
my clients on national cable advertising. I have spoken
with different network reps and have been told that they
can not provide reach, frequency, or TRP's. They have
said that they are not measured this way. Is this true?
The network reps have provided gross impressions (in
thousands). Is there a minimum threshold for this
- The Media Guru Answers(Saturday, September 05, 1998 ):
Everything which has its impressions measured in national tv has TRPs, which is merely a calculation: the division of impressions by the relevant population base, either in the cable network's coverage area or the total U.S.
Any metered measurement can produce the data for calculation of reach of schedules or the production of formulae which will allow estimation of reach.
The Guru would guess you are dealing with smaller networks whose ratings and reach would be unimpressive and therefore are not a part of the sales effort.
A 0.1 rating is the usual threshold for reporting in a printed report. There may be a requirement to earn this rating over a specified time span before even this level is reported. On the other hand, networks with ratings normally below this level are likely to be bought strictly for their content/environment, not their audience delivery.
- Friday, August 21, 1998 #2009
I'm having a difficult time trying to find any material
that will teach me how to use CPP when buying network and
spot radio. My contacts in the advertsing field tell me
that they learned how to use this formula through
experience. I know the formula for CPP. However, is there
any resource that will show me how to implement CPP when
buying network and spot radio? Something that will show
me some shortcuts or maybe some examples?
Thanks again for your help.
- The Media Guru Answers(Friday, August 21, 1998 ):
Once you know how to calculate CPP, its uses are pretty straightforward.
- CPP is an efficiency indicator. Media proposals you are considering can be ranked from lowest CPP to highest if efficency is a goal
- CPP can be a goal you give to sales people, e.g. "I'm buying a $100 Women 18-49 CPP, what avails do you have at that pricing?"
- CPP can be weighted with other factors like rating size or cume
- CPP can be used to caluculate cpm when the universe is known: CPP divided by 1% of the universe expressed in thousands yields cpm
- (this is only valid when rating and audience in thousands come from the same geography as they do in Network. In spot, where you may use a metro rating but TSA thousands , the formula is imprecise at best)
- CPP can be used as a bottom line number to compare possible schedules you are putting together
Remember - never average CPPs themselves; total the costs and total the ratings of schedules and calculate the bottom line CPP from the totals.
- Friday, July 31, 1998 #1981
Is there a formula that would indicate increases in
effectiveness if a direct mail campaign is supported
by other media? Example: TV and radio campaign to
increase awareness of a product followed by a targeted
mailing with a call to action.
- The Media Guru Answers(Friday, July 31, 1998 ):
Direct Marketing Association
(DMA) would be the best source for such information.
- Friday, July 24, 1998 #1973
I need help! I need to know the forumla (or formulas) for figuring the reach and frequency on a television schedule. I need it to be demo / and have the following information: universe, impressions and grps. What else do I need and what is the magic FORUMLA! At this point we are using the cumulative impressions into the universe to figure the reach - but could that be right? I don't think so - but the reach is what I need to figure (already have grp and freq is easy if I have reach!).
Please help - and thanks tons.
- The Media Guru Answers(Friday, July 24, 1998 ):
When you divide the accumulated impressions by the universe, your result is GRPs. There is no simple reach formula unless you already know GRPs and frequency. There are various very complicated algorithms for calculating reach for a given average rating size, known average duplication between programs used, etc. "Beta Bimodal" is one of the best known.
But today, Reach calculations are done by computer, using models built from Nielsen's actual measurements of net audience reach from meter-measured schedules.
Telmar, AMIC's sister company, is the leading provider of software for such analyses.
Before computers were commonplace, media planners had tables which gave reach for various GRP levels depending on demos, dayparts and duplication. These, too, were based on average Nielsen audience accumulation reports.
- Tuesday, July 21, 1998 #1966
Sports radio networks rarely, if ever, give CPMs and
TRPs for the proposals presented. When asked to
provide this info, they cop-out saying "well, other
agencies (i.e., JWT, Bozell, BBDO) buy our network."
I understand there is a premium to associate yourself
with a high profile sports team, but at what cost?
Without having resources to evaluate each and every
radio station in the network, how can I accurately
present these proposals to my clients? Currently, I
figure: total market CPP x average rating x number of
spots x number of games scheduled + added value
= total package value. Am I accurate?
- The Media Guru Answers(Wednesday, July 22, 1998 ):
When the Guru buys sports neworks, he gets audience and efficiency data. If you are saying that the networks give national data but not individual market rating, that's a somewhat different issue.If you are buying a team, its value is probably in its home market. If a network is only sold in total, what will you gain by identifying a weak station?
If you have all the data to execute your formula, you should do fine.
- Tuesday, June 09, 1998 #1886
how do i calculate reach of TV+PRESS, Is there a formula
- The Media Guru Answers(Tuesday, June 09, 1998 ):
As a rule, TV and press are thought to duplicate in a random pattern. That is, the random duplication formula is appropriate. The reach of each medium is treated as a decimal. To calculate net reach, we combine the probabilty of each medium's NOT reaching the target, to get the combined probability of neither reaching the target. The remaining people are the ones reached.
The formula works as follows when TV reach is 45 and press reach is 37.
People not reached by TV would be 0.55 of the target
People not reached by press would be 0.63 of target
Total people NOT reached are 0.55 x 0.63 or
0.35 of target.
The remainder of target is reached (1.0 - 0.35 = 0.65)
so reach is 65
- Friday, May 29, 1998 #1613
1.what is osto's model?
2.In case of an absence of duplication data for publications, how do l calculate
the effective reach using 2 or more media vehicles? in such a scenario, is it safe
to use the random theory even if multiple readership is negligible?
- The Media Guru Answers(Tuesday, June 02, 1998 ):
1) The Guru is not familiar with Osto's model. It may be specific to India, from where you are writing.
2) The Random method is a starting point. If you can find two other similar publications with measured duplication, you can use the duplication ratio from those publications. If you literally mean "effective reach," that is, reach at or above a minimum exposure level, then you need a more complex formula or a computer program like Telmar's ADplus.
- Thursday, May 28, 1998 #1610
1.Please, where can I find "Archives" by topic?
2.I have seen a table showing Awareness Level correlat
ed to Target GRPs.Could you, please, tell me how they
estimate Awareness Level?
3. I also have seen a table showing Audience engagement
in various activities when average commercial is aired.
Would you, please, tell me how the information is obtain
ed? Is it from a national panel? If yes, does this panel
also provide audience data? Thank you, Inocima.
- The Media Guru Answers(Tuesday, June 02, 1998 ):
1) The Guru Archives may be accessed from their link on the Media Guru Page. In the next few days, we will be adding a search engine to allow you to find all all past Guru answers on the topics of your choice.
2) The Guru isn't familiar with the table you have seen. Since you are writing from Brazil, it could be based on research totally unfamiliar to the Guru. The proper way for such a table to have been created would use just estimates of awareness, but actual survey results. An advertiser or agency which has conducted many awareness studies and correlated them with actual GRP's of the plans running in synchronization with the studies could create such a table.
In fact, just a few actual measurements could be the basis of a table if it is assumed that the awareness / GRP relationship follows some sort of curve as does the Reach / GRP relationship. The Guru is familiar with one formula for predicting awareness based on GRP, which came from analyzing several plans and surveys. In essence, it predicted that when there was any significant starting awareness, awareness declined in any week where there were less than 100 GRP.
3) Again, Brazil's audience engagement data is not familiar to the Guru. In the U.S. such data usually comes from secondary sources such as our Simmons or MRI, which ask these questions but are primarily print audience and product usage studies.
- Wednesday, May 20, 1998 #1599
Dear Media Guru,
I am developing and producing a short radio feature for barter syndication. On what basis do syndicators
typically set their ad rates? I realize that the rates
may be highly negotiable but are there any common
formulas (based on CPM, CPP or some other data)
used by syndicators to arrive at an "asking price"?
Also, can you recommend any resources helpful in
developing and marketing syndicated radio
programming? Thanks for your help.
- The Media Guru Answers(Wednesday, May 20, 1998 ):
Some of the issues in syndicated programming pricing are:
CPM or CPP better than spot radio pricing for similar audience size
Possible premium for an attractive program environment.
- %U.S. coverage
There are numerous radio syndication companies, handling everything from Rush Limbaugh to obscure musical formats. One good way to solicit response from -- or tips about -- the right resource would be to post a message about your program to the "Radio Media" discussion list. Send your request to join the discussion to RADIO-MEDIA@adsong.com
- Thursday, April 30, 1998 #1578
what is the mathematical relationship between the cpp and cpm, is there any formula linking this two concepts?
- The Media Guru Answers(Thursday, April 30, 1998 ):
CPP (Cost Per rating Point) is the cost of a number of media impressions equalling one per cent of a given population group (the specified "target"), as in Women 18-49 CPP.
CPM is the cost of 1000 target media impressions.
Therefore, the mathematical relationship depends on the number of thousands of people who equal one percent the target group.
For example, suppose there are one million women 18-49 in a market, and a radio spot has an audience of 20,000 women 18-49 at a price of $50.
The rating points generated by the spot are 2.0
(20,000 divided by 1,000,000).
The CPP is $25
($50 divided by 2.0)
The CPM is $2.50
($50 divided by 20[thousands])
Since CPP is the cost of impressions equal to 1% of the population, the CPM to CPP relationship is:
CPP divided by 1% of the population in thousands = CPM
In this case, $25 CPP divided by 10 [thousand]= $2.50 CPM
CPM times 1% of the population in thousands = CPP
While this works perfectly for national media, it can be tricky in local media unless geography is tightly defined. I.e. a broadcast CPM is usually defined as being on a Metro Area or DMA basis. CPM though, is often based on all impressions generated, even if outside the basic geography. Common geographic population definitions are essential to the accuracy of the formulas.
- Wednesday, March 25, 1998 #1553
How can be measurement error calculated? I would like to know is there any correlation between sample size and data validity? Thank you
- The Media Guru Answers(Monday, April 06, 1998 ):
Sample size and data reliability are in a "rule of squares" relationship:
A sample four times as large is twice as reliable. Note that "reliable" is the statistical term referring to the chances that a duplicate study with the same size random sample will get the same results, give or take a specified range of error.
"Validity" refers to correctness. It might have to do with whether a question asked can corectly produce a result that is desired. For example, a question like "What will you have for breakfast a week from Tuesday?" may not be a valid predictor of what people will actually eat on that day. But, with a proper sample, it will be reliable in predicting with a set degree of variability what people will eat.
The formula for calculation of error for a given sample is:
The Square root of (P x Q over N)
p = the percentage result to be tested (e.g. 10% of the people will have bacon)
q = the complement, or difference vs 100% (if p = 10% then q = 90%
n = the sample size
So, if a sample of 500 produces the result that 10% will have bacon, the sampling error for this result is
the square root of (10 x 90)÷500 or
so the answer of 10% should be read as "between 8.658 and 11.342" and
really means that 68% of the time the same study repeated would produce a percent of bacon eaters between 8.658 and 11.342.
If the sample is quadrupled, to 2000, then the error is halved, to 0.671.
- Tuesday, December 09, 1997 #1474
How do I put a dollar value on pr media placements? For example, how is a 6 column inch pr mention in the NY Times or a 30 -second mention on a radio station measured in terms of dollars? Is there a formula to use for PR, or do I use the straight advertising rate?
- The Media Guru Answers(Tuesday, December 09, 1997 ):
The Guru believes equal space in PR coverage is worth more
than an ad, but it's a judgement call how much more.
- Thursday, October 09, 1997 #1427
Does the length of the commercial determine the amount of grps reached? If I schedule a 30ss and achieve X amount of grps, and schedule a 15ss the same amount of times I achieve the same amount of grp's as with the 30ss?
- The Media Guru Answers(Friday, October 10, 1997 ):
Very simply, yes. Whether they are watching for 15 or 30
seconds, the audience of the commercial is the same, so
the GRPs are the same(never mind theories of channel
switching, or we'd be adjusting commercial audiences based
on partial viewing).
What can be confusing is that TV buyers often use formulas
requiring :15's to be treated as if they had half the
rating of a :30 in the same time slot, so that they can
most readily calculate a ":30 equivalent" c.p.m. or Cost
- Thursday, August 21, 1997 #1399
Question: What can you tell me about the mathematical
modeling system used in "advanced analytics?"
- The Media Guru Answers(Thursday, August 21, 1997 ):
Advanced analytics is a general description of new
techniques of modelling, the key to which is use of real
data. Not just sales, as a dependent variable, but
real quantification of all the elements of marketing mix:
media weight, budgeted coupon redemption, price promotion,
etc., as independent variables.
Each practitioner will have proprietary formulas to
determine what spending on what elements produces desired
sales results. The simple explanation is assembling all the
facts pertaining to a situation and letting the "answer"
emerge of its own accord, rather than hypothesizing an
answer and looking around for supporting facts.
The let the answer emerge from the facts approach is quite
old, what is new is the computer-supported capability to
maniipulate more data in more ways, and have real results
against which to judge outcomes.
- Tuesday, May 13, 1997 #1345
Since "PRICING WEB SITE ADVERTISING" was first
published (it's not dated but I'm guessing '96?) have
there been any 'advances' in the methodology for
pricing web advertising beyond either the ModemMedia
model or the alternatives suggested?
I am not an advertising professional (and they said us
geeks use obscure achronyms?), and I am also looking
for a concise FAQ type document that might explain the
formulae and jargon (CPM, Frequency, Impressions in
your excellent on-line dictionary and Depth which
isn't) within the context of web advertising. Are there
and other specific media terms (new or old) that are
pertinent in a web advertising context (I got page
view and hits)? Thank you.
- The Media Guru Answers(Wednesday, May 14, 1997 ):
The AMIC article was wriiten in the latter part of 1995, not
long after the appearance of the Internet
World May 1995 article which it discusses.
By the way, please be aware that AMIC has added a new area, called I-Trac, which discusses web terms and measurement
and which includes a Web Glossary
In terms of newer thinking, consider the critqued article's central
1.Determine the ratio of hits between the web site's log and
the number of file "hits" that make up the page carrying the
ad. Divide logged hits by number of hits making up the
page to calculate what we can call "page views." Then
call page views "reach."
Since then, the software which interprets log files has
developed so that it can distinguish pure "hits" from the more relevant page requests
or "page views" . Hits today is taken to refer to any
line in a log file, even errors. (Ad) Page requests is the
analog to traditional media's "impressions".
2.Determine repeat viewing of that
page and call that frequency.
We more commonly use
"frequency" in terms of whole campaigns
success of viewings of that billboard ad in moving readers
to the actual web site and call that "depth."
measurement concept has come to be called "click-through" or ad click rate. Depth was a term
only used as defined in this Internet World article.
Today pricing is generally based on cost per thousand
(CPM) impressions. Rates seem to range from $15 cpm for the
broadest, general audience sites' rotating banners, through
$50 or so for search engines' keyword banners up to $100+ for
"premium audience" on highly targeted business to business
Another pricing model growing in popularity is "price per
click," which charges for each vistor who clicks on a
banner. The problem here is that the site hosting the
banner must rely on the creative to generate viewr response
-- it isn't all the effect of the web site itself. Therre
is considerable literature today about how to influence
clicks, as well as a growing body of research which argues
for the awareness building effects of the banners,
regardless of clicking response.
Finally, simple revenue based models are the rising
concept. In this, sites hosting banners are compensated
with a portion of the transaction revenue generated by web
surfers they send to retail type sites. An offshoot of this
is a model for ad placement agency compensation based on
the revenue generated by their placement of ads at
- Wednesday, January 29, 1997 #1065
I'm finding very hard to calculate the price of an advertise on the web.DO have any tip or formula that could help me ? Thank you very much !
- The Media Guru Answers(Thursday, January 30, 1997 ):
What information or goal are you starting with? As a guide line, search engine keyword banners may cost between $30-$70 per thousand ad impressions.
- Monday, January 27, 1997 #1067
My client is requiring me to use adjustment percentages whencalculating grp's in print. I was always taught that reach x frequency= GRP's. Now if I calculate the adjustment to my grp's, the formula no longer works. Is this correct, or do I have to do something else to my reach/frequency? Help!!!
- The Media Guru Answers(Tuesday, January 28, 1997 ):
There are various approaches. If the GRP adjustment is just an index reflecting characteristics of the vehicles and their audiences, it may be sufficient to show R/F/GRP/AdjGRP
If the adjustments are meant to change actual value of the GRP, it is usual to recalculate reach from the new, adjusted GRP. Since print r&f is usually calculated from actual schedules, via a "black box" algorithym, rather than from a grp "curve," this may be impractical. If your system allows you to enter factors for each publication before calculating reach, that may solve your problem.
Lastly, even with adjusted GRP to represent some abstraction, the people reached would not be reached at a different average frequency, so one quick and dirty answer, if you must use adjusted grp, is just to divide them by the original frequency, to get reach.
It's similar to the concept of changing a spot coverage area, broadcast r/f to its national equivalent: The GRPs are weighted by the coverage area % and the frequencyremains constant, to calculate the reach.
- Tuesday, December 17, 1996 #1092
Dear Media Guru Guy:Where can I find out more info on standard error? First, how is it calculated, or what affects standard error? Second, I'm thinking about magazine readership research, and I'm wondering what standard errors some of the popular studies have (MRI or Simmons, for example). And then, I'm also curious as to what, among media gurus, is considered an acceptable or unacceptable error. Do the same standards apply for other media research studies, for example, Nielsen ratings? Thanks Mr. Guru.
- The Media Guru Answers(Friday, December 20, 1996 ):
Standard error reflects the range of "tolerance," due to sample size, around the reported answer where the "truth" lies. Inother words, statistical data like "10% of women 18-49 read MagazineX" in reality means that within the range of error expected, if thesame study were repeated 100 times, with a sample of 225, the resultwould between 8 and 12 percent, 68 times out of the 100.
The formula isthe square root of (P times Q divided by N)
P= the percentage to be tested
( e.g. the 10% in the Guru's example, above)
Q=100 minus P ( 90% in our example)
N= total sample size (225 in our example)
10 X 90 = 900
900 divided by 225 = 4
square root of 4 = 2
One standard error is the amount of variance sampling causes 68% of the time.
So, at one standard error, 10% is between 8% and 12%with 68% "confidence" At 2 standard errors or within+/- 4 points, or6 to 14% we have an answer we are confident our research will repeat95% of the time. This is why the concept is also referred to as"reliability". It is really way to express confidence that the samesampling procedure will produce the same result.
Most statistical texts can give you considerably more on the topic.
- Monday, August 05, 1996 #1171
In regards to print advertising, what is a wear-out report? What data do I need to complete this report (reach, frequency, formulas)?
- The Media Guru Answers(Thursday, August 08, 1996 ):
The Guru has discussed Wear Out previously (see below July 17 and May 7).
A wear out report would state the status of various print executions in your campaign in comparison to the wear out standard you have established.
Clients have a way of asking the wear out question without setting a standard or even being able to decide how to set one.
Essentially an ad is worn out when it loses all or most of its ability to accomplish its marketing purpose with its target. The purpose may be as simple as product sales, or lead generation in a direct response campaign, or it may be as difficult to define as building brand imagery or awareness of a specific product benefit. Since directly relating any of these to a specific ad would require custom research, it is typical to use whatever research has been done in the past as related to easily modelled media measurements, such as reach, frequency, GRPs or quintiles.
For example if in the past, a custom study showed the average ad was worn out at a time when the planners knew that 80% of the target had seen it 8 or more times, or when the frequency in the top 2 quintiles passed 30. (Don't use these examplenumbers). Naturally, different ads perform differently, but you will need to work on an average basis.
A wear out report then becomes a matter of reporting something like how many of thetarget have seen the ad at least "x" times, or that the frequency in the top 2quintiles will exceed the standard measure as of a certain month of the schedule, or"X" number of GRPs will have run for the ad by some date.
The key is knowing how one of these media measures relate to your wear out standard. Then the report is a simple task.
- Thursday, June 27, 1996 #1188
Is there an established formula for setting rates for non-url linked advertising on web pages (i.e. display only advertising with no links to other sites)?
- The Media Guru Answers(Thursday, June 27, 1996 ):
Nothing "established," but there are some good insights at the following sites:San Jose Mercury News' "Advertising on the World Wide Web With Mercury Center"Newspaper Advertising Association: Tracking Audience on the Web, by Jim ConnaghanAMIC Research Monitor: Pricing Web Site Advertising, A Media Buyers View by Abbott Wool
- Friday, March 08, 1996 #1266
Guru:Is there a formula for calculating reach & frequency for trade vehicles.
- The Media Guru Answers(Sunday, March 10, 1996 ):
There is no truly simple formula for calculating reach and frequency of any medium. The key datain print R&F are pair-wise duplication between different vehicles and between two or more insertions in the same vehicle.
As the number of insertions in a plan increase, the number of data elements to include in a formula increase. The number of possible pairings for just a 10 insertion plan is 45 ((n x n-1) / 2).
Telmar among others, offers software designed to quickly perform these calculations on defined schedules of media measured by SMRB, MRI, MMR, J.D. Power or others. Using measured media as prototypes, reach of various schedules you might want to consider could then be calculated. From these numerous calculations, you could, by regression analysis, develop a "simple" formula of the form y=ax+b to calculate frequency based on GRP of typical plans of the sort you run in these media (y is frequency; x is grp; a and b are factors from the regression).
A formula of this kind is very specific to the audience dynamics of the media vehicles involved. Please understand, this is not a recommended technique, merely a response to your question.
- Wednesday, February 21, 1996 #1755
Dear Media Guru- I have a two part question , both dealing with the same subject, tv sampling error. Suppose ER gets a 20% rating and Seinfeld gets an 18%, both off a sample of 1000 resondents. What are the odds of there being absolutely no difference between these two ratings? This is not as simple as looking up the standard error of each rating. I remember that it has something to do with the standard error of the difference, but I just can't recall the calculating process.Could you please explain? Then to complicate matters, I'm looking at the same phenonena on a grander scale. Suppose the estimated delivery in rating points for a tv schedule is 1000 grps and it underdelivers by 10%- ie. 900 grps. What is the likelihood that the difference had to do with pure chance ( sampling error) and how do I calculate that? I know this is more difficult since you have to account for buying many programs in the estimate and the actual. Naturally, we are assuming that the error differences are all due to sampling, and not the idiosyncrasies of the marketplace or the impurity of the sample. In this case I know the answer is going to be technical, but that is what I need. Thanks
- The Media Guru Answers(Friday, February 23, 1996 ):
The Guru loves this kind of stuff. The answer is technical but hopefully, in simple terms.
First, if ER has a 20 rating and Seinfeld has 18, with a sample of 1000 (for that demographic), then the ER 20 rating's standard error is +/- 1.265 while Seinfeld's 18's is 1.215 (See formulas in the Jan 25 18:23 Guru Q&A below).
Note that the absolute size of the error on the 20 is larger but it is relatively smaller. Also note that the range of these errors is such that they can make the two programs' ratings equal: 20 - 1.265 = 18.735 which overlaps 18 + 1.215 or 19.215.
There is a 68% probablity that these two ratings fall within this range. But the swing could go either way on either number. And could fall anywhere within the +/- range specified
There is a 90% probabilty that these two ratings fall within +/- 1.999 on the 18 and +/- 2.081 on the 20. The odds are 95% that they fall within +/- 2.381 for 18 and 2.479 for the 20.
These odds actually relate to reliabilty. That is, if you repeat the same rating study 100 times with the same actual facts existing, 68% of those studies will give ER a rating between 18.735 and 21.265.
Now the 1000 GRP underdelivered by 10% is different As the beginning of the explanation showed, while there is a swing around any rating (a 5 would be +/- 0.689 in the same study), the odds equally favor underestimates and overestimates. This is the same as the reason why small samples don't necessarily underestimate ratings. So in 1000 GRPs made up of 500 spots with an average 2 rating, the sampling error on the individual ratings somewhat cancels out.
To calculate this in an Arbitron measured radio buy using a single survey and one station, for example, the formula is
GRP x ((100 x #spots) - GRP) / sample x Factor)))
"Factor" is from a table provided, specific to demographic and #quarter hours in the daypart of the buy.
So, if your 1000 GRP were based on Adults 18-49 ( with a 1000 A18-49 sample), and a Mon-Fri, 6a-7p schedule, the calculation would be:
(1000 x ((100 x 500) -1000) / (1000 x 2.42)))
or +/- 143 GRP at the 68% confidence interval. Obviously, if the average rating were higher, hence fewer spots or if the sample was larger the variance would be smaller. With an average 20 rating, the swing is about +/- 40 GRP.
So, depending on average ratings and sample sizes, the 10% underdelivery could be within the range of standard error.
- Friday, February 16, 1996 #1760
Dear Mr. Guru, Thank you for your last reponse on how to calculate GRP's. You had mentioned that you had explained it fully except for Neilson's calculation methodology. I would be interested in hearing more about this method of calculation as well. Also, is there a "better" way to measure the actual "Impact" an ad campaign has had if you know the actual length of each ad, the frequency the ads ran and the channels(and shows) that they ran during. ie. frequency X length X Audience(rate for each time slot)?? This is obviously a simplified formula, but your feedback on this would be greatly appreciated. Lastly, for television advertising, what are some of the other accepted methods of measurement. Thanks (Again) email@example.com
- The Media Guru Answers(Friday, February 16, 1996 ):
It is Neilsen's survey methodology that wasn't covered. They would use the same calculation formulae. The full description of Neilsens methodologies for People Meter, household meter and diary would cover several pages. Contact Neilsen who will be happy to send you methodology booklets.
Regarding "impact" there are as many ways to evaluate this as there are advertisers.
Some advertisers use a factor for copy length based on norms from recall tests. For example, 75% of a :30 is a typical value for a :15.
Some use attentiveness by daypart.
Some use a combination of the two factors.
Some apply the factors to GRP as an indicator; some apply to GRPs and then estimate reach from those adjusted GRPs as an impact indicator.
The frequency of a schedule, as discussed so far, refers to the average frequency of exposure for all pesons reached.
There are those who use "effective reach," counting only persons reached at least 3 times (or any designated minimum) when evaluating the impact of a schedule.
- Thursday, February 15, 1996 #1762
What is the actual formula for calculating GRP's
- The Media Guru Answers(Thursday, February 15, 1996 ):
There are various formulae, depending on from what data you are working:
GRP = Reach x frequency
GRP = Average rating x number of advertisements
GRP = The sum of the ratings of all the advertisments in a schedule
GRP =The total impressions delivered (i.e. audience among a specific demographic group, expressed in raw numbers of people X number of advertisements) divided by population universe for that demograpic.
- Thursday, February 15, 1996 #1761
I would like to know a DETAILED calculation for GRP's for Television advertising. I assume the frequency is the number of times the ad ran across all channels. But how do I calulate the Reach for a T.V. AD. Is it based on the rate cards of the networks?(if so, how) or is it based on direct audience measurement. As much detail as possible would be greatly appreciated. firstname.lastname@example.org
- The Media Guru Answers(Thursday, February 15, 1996 ):
Calculation of GRP does not depend on knowing reach, though reach x frequency is ONE formula. Reach is the more complex calculation, GRP is relatively simple (see other formulae in the adjoining question).
Reach has no relationship at all to rates, nor to commercial length, for that matter. Audience research surveys such as Nielsen can tell us the audience of individual programs. The net unduplicated audience, or reach, of actual advertisers' schedules, examined over time covered by a given survey period, typically four weeks, can be determined.
When many such scehdules, usually thousands, have been examined in that way, "curves" on a graph can be drawn representing the intersections of reach values with schedules' GRPs. The graph curves because each added announcement adds fewer new, unduplicated people toi the reach of the schedule.
The curve can be expressed as a formula y = ax+b, which then can be built into the computer model which media planners use to quickly calculate reach from given GRPs and sometimes other descriptive details of scheduling, such as average ratings, numbers of different networks or programs, etc.
The Guru is now nearly out of details unless Nielsen survey methodology is of interest.
- Thursday, January 25, 1996 #1774
I have a total universe of 9500 people and I would like to know how big a sample I would need for as good study. This is for a phone interview.
- The Media Guru Answers(Friday, February 02, 1996 ):
The population size is a relatively insignificant factor in calculating reliability of a sample; 500 respondents is just about as reliable in surveying a small town as for the United States as a whole.
To plan a "good study," you need to consider the size of the typical answer you will get.
If your typical response will be 50% of respondents said "yes" then a far smaller sample could be suitable than if answers are "10% use brand B."
You also need to decide what level of reliabilty you require, or how much swing, +/-, is acceptable and to what tolerance.
If your sample size is 500, a 50% answer is actually reliable +/- 4.4 percentage points, 95% of the time and +/- 3.7 points 90% of the time.
If the sample size is 125, a 50% answer is reliable +/- 8.8 points, 95% of the time. This is double the relative error of the 500 sample (rule of thumb, 4x as much sample reduces error by half).
If the answers anticipated were 10%, then for the 125 sample it varies +/- 5.2 points, or over 50% relative error.
A 10% answer from a 500 total sample yields +/- 2.6% points at 95% tolerance or 26% relative error, which is possibly acceptable for your need.
To examine other possibilities, the formula for 95% tolerance is:
1.96 x squareroot of ((PxQ)/N)
P = the answer size expressed as a decimal fraction
Q = the remaing fraction of the sample
N = the total sample size
To examine 90% tolerance, substitute 1.645 for 1.96
- Thursday, January 04, 1996 #1802
How do television and radio advertisers value an impression? That is, if someone advertises on television is there a formula used to determine prices for :15, :30 and :60 spots? Thanks.
- The Media Guru Answers(Friday, February 02, 1996 ):
As a general rule, :30 impressions are the standard reference for TV and :60 for radio. "value" and "price" may or may not correlate:
In TV, a :60 is usually double a :30's price but has the same value in reach. Some advertisers use attentiveness or recall factors to adjust the "value" of a :60 vs a :30 impression. Your question focuses on pricing.
In most cases, :15's are priced at 50% of 30's, but there are instances where 65 or 75% is used.
In radio, :60 is the standard, with :30's typically priced at 80-85% and :15's not in use. Some stations today, especially top rockers with a sensitivity about clutter and inventory sell "units" not differentiating between :60's and :30's in price.