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Guru Search Results: 34 matches were found

Wednesday, April 04, 2007 #7309
Who is the founder of Random Media combination theory? Thank you

The Media Guru Answers(Wednesday, April 04, 2007 ):
The Guru would not consider this a "theory" per se, nor that there is a "founder."

The "random" concept is basic statistics: when the probablity of occurrence of two unrelated phenomena is known, then the probablity of both occurring is calculated by the product of the two probabilites. In media terms, this means:

  • The reach of a given medium is the probability of the audience being exposed to the schedule
  • So 30% reach is 0.30 probability of exposure
  • The combined reach of a media schedule (say print) with a 30 reach and another media schedule for the same advertiser (say tv) with a 60 reach is actually calculated by figuring the probability that neither reached the target:

    0.7 probability that print didn't reach the target x 0.4 probablity that TV didn't reach the target = 0.28 probability that neither reached the target or 72% reach (1.0 - 0.28 = 0.72)

Multiplying the two reaches together gives the probability of both reaching the target, which is not reach, but duplication.

Of course, the reach of different media schedules reaching the same target are not truly unrelated phenomena, and various adjustments to pure random have been promulgated by many practitioners.


Friday, April 28, 2006 #7132
How do I calculate reach?

The Media Guru Answers(Friday, April 28, 2006 ):
You need a computer with software such as that offered by Telmar.

The calculation is extremely complex. For example, in print, as input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables.


Wednesday, December 28, 2005 #7073
Can you tell me how to calculate reach/frequency without a software program? We have the TRPs, daypart mix, and I'm sure we can find out population estimates for the demo. Thanks for your help.

The Media Guru Answers(Wednesday, December 28, 2005 ):
You need a computer with software such as that offered by Telmar.

The calculation is extremely complex. For example, in print, as input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta Binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables.


Friday, November 11, 2005 #7043
Dear Guru ,how can i calculate 5+ reach with in a given GRP and universe for a TV PLAN.May be it depends on the program and channel mix but I want to know the basic calculation ,plz

The Media Guru Answers(Sunday, November 13, 2005 ):
You need a computer with software such as that offered by Telmar.

The calculation is extremely complex. For example, in print, as input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables


Friday, August 12, 2005 #6993
Back when I started in media (1984) I learned a way to hand-calculate combined reach/frequency. Say adding together a tv and radio schedule. I unlearned it over the years, especially when I had software that did it for me. Now I don't have the software anymore and have been asked to do a combined R/F. Do you have that formula? Thanks.

The Media Guru Answers(Friday, August 12, 2005 ):
Click here to see past Guru responses about combining reaches


Thursday, June 09, 2005 #6947
We have put together a campaign consiting of print & television in a few spot markets. Is it possible to determine the reach & frequency for those persons who will only see the TV and only see the print? How is it possible to know who has seen only print & only TV?

The Media Guru Answers(Saturday, June 11, 2005 ):
  1. calculate TV reach
  2. calculate print reach
  3. calculate combined reach (presumably, you have gotten this far)
Now it's simply addition and subtraction:

Suppose you have found the following:

TV reach = 50
Print reach = 40
combined reach = 70.

Therefore, 20 reach points of the print are added to TV (saw only print) and 20 duplicated (also saw) TV.

Further, 30 points of the TV are added to print (saw TV only), and that same 20 points as above are duplicated.

So it breaks down to

TV only = 30 reach points
Print only= 20 reach points
saw both = 20 reach points
Total reach = 70


Wednesday, May 25, 2005 #6937
Thank you for your answer about internet grps(#6936). Another question would be, can we calculate reach for internet? and how about reach for a hispanic target

The Media Guru Answers(Wednesday, May 25, 2005 ):
Calculating reach is ususally done in one of two ways:
Using a respondent level audience measurement such as Nielsen//Netratings or comScore-MediaMetrix, one tracks the actual use by the relevant demographic within the sample against the schedule run.

More practically, one obtains a series of such measurements and builds a model, so that one can then genralize from schedules run in the future, using variable such as # of impressions, number of sites in the mix, share of page loads on the sites, etc.

The issues are what portion of the sites' reach does your schedule get and what is the duplication between sites' audiences.

For example, Yahoo might reach 40% of all those online in a month, but your buy will probably appear in less than 0.1% of all Yahoo page loads. And how many of the persons exposed to your Yahoo buy will also be exposed to your buy on MiGente.com?

Since Hispanic audience is measure by both services, the Hispanic issues are no more difficult in this scenario.

As a ballpark sort of estimate, most major sites ought to be able to tell you the number of unique visitors exposed to your schedule. This number, divided by the relevant universe will give you an estimate of reach on that site. You can combine sites' reaches by random probability unless you can get site duplication estimates from the sites.


Tuesday, April 19, 2005 #6903
Dear Media Guru, Please help me figure out the combined reach and frequency of a multi-station TV buy. To find the average frequency, would I add the frequencies of the stations and then divide by the number of stations? Do I then multiply it by the total number of GRPs to calculate the reach? Since I do not have access to a software program, I need to calculate this manually. I'm in desparate need of your help since these figures are due soon. Thank you.

The Media Guru Answers(Sunday, April 24, 2005 ):
Frequencies are never additive. A specific model is the only accurate way to combine station reaches. The reach may be divided into the sum of GRP to calculate the average frequency.

A very rough estimation of combined reach might be calculated by a string of random probabilty parings (i.e. pair two stations and then combine the next with those and combine the next with the cume of the three and so on). Because this is "random" and does not account for the greater likelihood of any TV viewers to view other tv, the result will be overstated, by at least 10%.


Friday, April 01, 2005 #6875
Hi, Guru. I need to calculate the media mix. I have a set of media, some of them are measured by one research company, some of them by another, some of them are not measuring at all, but i can estimate their reach for my target audicence. All media are using on the same market at the same time. There is no problem to estimate the combined reach for the whole media mix. The question is - is it correct to combine the GRPs, gained by each media to the 'Total GRP of the campaign", which can help to estimate the frequency of the full campaign (for all media in the mix together)? Thanks, Luba.

The Media Guru Answers(Sunday, April 03, 2005 ):
From one perspective, a GRP is a GRP, simply and litereally a "gross" representation of all audience impressions. This view is most applicable for the purpose you are considering, leading to a frequencty calculation against the reach calculation.

On the other hand, it is not uncommon to apply weights to GRPs representing their medium's relative attentiveness or message retention, etc. But this approach is most applicable at the stage where media are being comared for inclusion in the plan or allocating a proportion of budget


Tuesday, December 16, 2003 #6315
How do you calculate combined frequency. If I have a cable plan in a market with a frequency of 2.6 and a broadcast tv plan with a frequency of 6.6 - what is the combined frequency?

The Media Guru Answers(Saturday, December 20, 2003 ):
The Guru will assume you are referring to average frequency, typically considered for a four week period. One actually calculates the combined reach and GRPs and then figures the "combined" frequency. Consider the following table. If you had run 400 GRP in broadcast and had 61 reach there would be 6.6 average frequency. If you also had 100 GRP of cable and a reach of 38, there would be an average frequency of 2.6.

GRPs are simply additive for a total of 500. reaches must be combined by a system that recognizes duplication; "random probability" will overstate a bit when you are working with two related elements such as different kinds of TV. Probability might have estimated a combined reach of 76 here but let's suppose your algorithm estimates 72.

In any case, the combined average frequency is calculated thus: divide the combined GRP (500) by the combined reach (72) which equals 6.9; see below:

Element
reach
Freq.
GRP
Broadcast
61
6.6
400
Cable
38
2.6
100
Total
72
6.9
500


Saturday, November 29, 2003 #6282
Is there a method for "manually" calculating the reach/frequency of network TV/radio? I know other options exist (Telmar, for example) but would prefer to have my students do it this way if possible.

The Media Guru Answers(Sunday, November 30, 2003 ):
25-30+ years ago, planners worked with tables of GRPs by medium or program frequency, etc, baseds on averages of many fully calculated actual measurements but not full scale calculation, which would involve treating each commerical individually. While there might be some value in learning how to take a set of observations and develop a curve, trying to make these base calculations for each plan seems pointless.

The purely manual calculation is extremely complex. For example, in print, as input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables


Tuesday, June 10, 2003 #6006
Dear Guru, I have the circulation figures and the readership duplication percentage of various dailies. How can I calculate the net reach? What are the other variables required to calculate net reach? Thanx, Toolie, Bangladesh.

The Media Guru Answers(Sunday, June 15, 2003 ):
You need a computer with software such as that offered by Telmar.

The calculation is extremely complex. For example, in print, as input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables


Saturday, March 08, 2003 #5871
Dear Guru, I encounter some more questions which I am unsure. I learnt that we can calculate combined reach of different media vehicles in one medium and combined reach of different media (e.g. TV, Magazine etc.) and same for frequency. However, how can I applied tohse in an advertising flowchart? where I need to indicate monthly reach, monthly frequency and GRPs for different media vehicles+media (?) To do it manually, do we really calculate first combined reach and frequency of all media vehicles within 1 medium first than use the final combined reach % to calculate with other media to get the Montly reach & frequency & grps in the adv flowchart....it will be quite tedious....I am confused...please help!

The Media Guru Answers(Sunday, March 09, 2003 ):
The Guru does not understand your confusion. You say you understand how to calculate the reach of several vehicles in one medium and how to combine the reaches of several media.

One thing you must understand is that reach is always calculated over a specified period of time. The standard period is four weeks. Often, when print is the only medium involved, one month is used because this is virtually the same as four weeks and monthly magazines fit readily. However, it should be recognized that variations in issue dates muddy the time cycle, and that monthly magazines' audiences cume over a longer period than one month.

In any case, whether the flow chart is divided into 12 months or 13 four-week periods, the process is simply a matter of looking at the schedule that will run in each of these periods and calculating the R/F/GRP for each. The is not any kind of standard that establishes that a flow chart should show R&F for every month. When schedules are fairly consistent, it is probably more common to show the average 4-week R&F within each quarter, or whatever is needed to give a clear understanding of the plan's communications levels.

And yes, if you are doing the work manually, it is tedious.


Saturday, February 15, 2003 #5841
Can you please tell me how to do the Sainsbury formula in order to calculate campaign reach & frequency?

The Media Guru Answers(Monday, February 17, 2003 ):
Click here to see past Guru responses about Sainsbury.

To do the kind of calculation you probably want, you need a computer with software such as that offered by Telmar.

The calculation is extremely complex. For example, in print, as input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables


Friday, February 07, 2003 #5815
We've been asked to estimate reach/frequency/etc. for a plan that includes USA Today, newspapers in 8-10 major markets, spot radio in 5 markets, metro traffic in 8-10 markets, and national magazines. I think this is impossible, but can you think of any way I can provide the client with a decent estimate? I was thinking I could start by pulling delivery for USAT, magazines, New York Times, and then somehow estimating the rest.

The Media Guru Answers(Saturday, February 08, 2003 ):
The Guru sees no problem, and so does not quit understand your question perhaps. Assuming you know what reach and frequency is, you can readily determine the reach of each one of the media you mention. Most simply, you can combine them by Random Probability . Most reach and frequency systems on the market, like our own eTelmar, can do this for you. The only "trick" is accounting for the different geographies, but that's just artithmetic, and easy if you look at all the percentage reaches as their equivalent in thousands.


Thursday, September 26, 2002 #5532
How can I calculate reach & frecuency?

The Media Guru Answers(Thursday, September 26, 2002 ):
You need a computer with software such as that offered by Telmar.

The calculation is extremely complex. In print, for example, as input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables


Friday, August 16, 2002 #5468
I need to know, What is the data that I can use to calculate newspaper reach?

The Media Guru Answers(Friday, August 16, 2002 ):
As in your adjacent query, you need a computer with software such as that offered by Telmar.

The calculation is extremely complex. As input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables.

Try The Newspaper Advertising Association for some general estimates.


Thursday, January 31, 2002 #5039
calculate reach and frequency

The Media Guru Answers(Thursday, January 31, 2002 ):
You need a computer with software such as that offered by Telmar.

The calculation is extremely complex. As input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables


Tuesday, January 22, 2002 #5026
Now that Outdoor can be mixed with other media, what is your thinking on how do the number of uses effect the frequency distribution? Should we be transferring GRP's, number of days or number of boards times days? How does this effect the frequency of the programs?

The Media Guru Answers(Thursday, January 31, 2002 ):
Outdoor could always be mixed with other media, so the Guru presumes you mean that the media software you use now has the ability to calculate reach and frequency for the combined media. Your question is probably answered in the software's manual.


Tuesday, January 22, 2002 #5025
What do I need to calculate reach for print and what is the formula?

The Media Guru Answers(Wednesday, January 23, 2002 ):
You need a computer with software such as that offered by Telmar.

The calculation is extremely complex. As input, you need average issue audience, duplication between issues of the same publication and duplication between each possible pair of different publications. These must be combined using a complex formula such as the Beta-binomial function. There are variants of this formula, which might be preferred, depending on media type and other variables


Friday, June 29, 2001 #4538
Hello again, 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.


Friday, May 04, 2001 #4368
Media Guru, please help. How do I calculate reach and frequency for a two-week, two-newspaper buy? We are placing 4 ads per week (total of 8 ads for the schedule) on Newspaper #1, which has a maximum reach of 9% of our target. Newspaper #2 will carry 2 ads per week (4 ads for the schedule) with a maximum reach of 23% of our target. Please advise. Thanks!

The Media Guru Answers(Sunday, May 06, 2001 ):
Find some example newspaper R&Fs at The Newspaper Advertsing Associations Marketscope site.

In very general terms, you can estimate some parameters. If newspaper A has a 9% maximum reach, it probably has a single copy reach of around 7%.

If B has a maximum of 23%, then it likely has single copy reach around 20%. So the outside bounds of reach for your schedule are a minimum of 20, but more likely closer to 25, the random combination of the two papers' single copies. The outside maximum is 32 ( the 9% plus the 23% maxima), but more likely closer to 30 (random again).

A solid estimate of 25-30 reach for your schedule should be good enough, but you could use the eTelmar pay-per-use system for a specific calculation.

Frequency, of course, will be the sum of the single copy audeinces of all insertions (GRP) ÷ the reach estimate.


Monday, January 08, 2001 #4087
Guru, First off, just wanted to let you know that I find this to be one of the most usefull sites on the web - as a management consultant in need of a crash course on media planning, the information found in these pages has proven invaluable...Now, on to my question: I am working on the launch of a branded consumer services play (auto related), and am trying to build a marketing budget from the bottom up, rather than as a strict % of sales. I have modeled an overly simplified media plan, and am looking for guidance on placeholders to use for weights (TRP) for TV and Radio, # of weekly inserts for newspaper, and showing level for outdoor. I know there are numerous factors and considerations I am leaving out (I know the GURU doesn't like sweeping generalizations), but I need a place to start. Goal: generate "substantial awareness" (think Midas, Maaco). Thanks for your insights.

The Media Guru Answers(Thursday, January 11, 2001 ):
The Guru thanks you for the compliments.

Keep in mind that while "substantial awareness" may be a snappy phrase for discussion of plans, you need to quantify such a term in order to quantify the building blocks of getting there.

Let's suppose we decide the goal is 80% ad awareness among the target within a given campaign period. Therefore, your advertising must reach at least 80% of the target in that period, with enough frequency for the message to penetrate and stick, let's say at least three times.

Now, you can calculate that generating that reach in TV will call for a certain number of TRP (you can use the media software at eTelmar for calculations). Or you can examine getting that reach with radio or a combination of TV and radio.

Outdoor will generate high reach more efficiently than either, with a #25 showing, but outdoor's necessary simplicity of message may not stand alone in filling your needs.

Newspaper has its own contribution and you need to judge from a marketing perspective whther you need a small store-locator ad every day, a full page branding message once a week, or some other approach, if any.


Monday, June 12, 2000 #3547
I am buying radio in two different markets - one is a large market which is measured by Arbitron. The other is a small market where I get the ratings through Arbitron county measuring. The two cities are only 45 miles apart and there is a large amount of radio overlap. Is there any way to figure an accurate combined reach & frequency? Thanks.

The Media Guru Answers(Monday, June 12, 2000 ):
First, define "market." If these radio markets are both in the same DMA, and you want DMA R&F, add the two stations' reach in thousands and divide by DMA universe. If they are in two different Metros, calculate reach within each and do a weighted average of the two:
  • Metro "A" target population = 100,000
  • Metro "B" target population = 20,000
  • Metro "A" target reach = 40% (40,000)
  • Metro "B" target reach = 55% (11,000)
  • combined, total coverage area reach = 40,000 + 11,000 100,000 + 20,000, or 42.5%


Wednesday, April 12, 2000 #3392
Guru, I've never used a planning program as most of my planning has been national print and outdoor, local broadcast, and things I've felt I can handle on my own.I've seen so many planning programs and websites for planning it's hard to tell the good from the bad. Have you ever evaluated planning programs and, if you have, can you recommened one or two? Thanks

The Media Guru Answers(Wednesday, April 12, 2000 ):
To the Guru, the term "planning program" means programs like Telmar's AdPlus or Telmar's full set of individual media analysis programs or the eTelmar online suite of media programs.

Such programs calculate reach, frequency, effective reach, frequency distribution, and quintiles for individual media plus combinations of media as well as cross-tabulations and rankers from media audience databases. Flow charting is also a typical option.

These programs don't actually create media plans, that is determine how much budget to invest in each medium, ad units to use, and scheduling. There are such programs on the drawing board, but require that the planner quantify and factor those concepts which would be subjective judgements.


Thursday, March 16, 2000 #3326
Dear Guru: 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:

  1. Work with two reaches at a time
  2. Treat the reach of each medium as a decimal (50 reach is 0.5)
  3. Add reach of medium A and medium B
  4. Multiply reach of medium A by reach of medium B
  5. Subtract the product of the multiplication from the sum of the addition

Example:

  • 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.


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 #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.


Monday, May 10, 1999 #2499
How do you calculate reach "in-market", and are you to combine that with the national numbers? How is this done? Thanks. We are trying to show total "in-market" delivery. Also, back to the average 4 week dilemma, is it only relevant when looking at sustaining levels of a continuity plan? Or would you show average four week even in a launch, retail, or promotional type heavy-up situation? Thanks as always.

The Media Guru Answers(Monday, May 10, 1999 ):
Suppose you had national media with a reach of 40% and a local media plan delivering 50%.

You would combine the national reach of 40% with the local 50%. If you care to go the extra step, you could analyze local variation in delivery of the national plan and adjust the local delivery of the national media before combining with the local. Or if you run only national media you can look at the locally delivered weight to caculate the in-market reach resulting from national media, as if it were local spot media.

Four weeks is a traditional standard measurement period. This standard goes back to the days of the dominance of monthly magazines as an advertising medium. There are numerous ways this rule of thumb is used. Some look at "4-weeks-when-in" and examine four weeks worth of average activity no matter ho many active weeks a plan has. This focuses on the rate of advertising rather than the quantity. Other focus on cume of whatever number of weeks. One has to make a judgement of what tells the story best. The judgement can be made differently when you are comparing possible plans and when you are trying to quantify potential effects on awareness, sales, etc.


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

    73% reach.

Telmar's "Media Mix" program uses these assumptions.


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


Monday, August 18, 1997 #1392
Is there a company, or a source, which is capable of measuring reach/Frequency of any/all media combined?

The Media Guru Answers(Monday, August 18, 1997 ):
The ADPlus system, from our sister company Telmar, can combine reach and frequency from all media. Some media must first be calculated by other systems and then be brought into ADplus for combining


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) darrylw@conceptus.on.ca

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.



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