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Media Guru

Guru Search Results: 41 matches were found

Tuesday, April 21, 2015 #9065
Dear Guru, how can I calculate reach if I have total GRP for target group and audience potential?

The Media Guru Answers(Tuesday, April 21, 2015 ):
You don't have sufficient infoirmation. Even if you did, you would need a computer with software such as that offered by Telmar or online through eTelmar.

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, June 06, 2014 #8980
Hello Guru, i want to ask you about TV Reach & Frequency. Suppose i have following GRPs : 766 Add Spots :2,939 Number of Spots Affinity Index : 111 then how can we calculate reach & Frequency with out using software....please let me know !!!!!

The Media Guru Answers(Tuesday, June 10, 2014 ):
This can't be done with the information provided.


Thursday, July 18, 2013 #8868
Hi Media Guru How would you calculate online media reach curves? Since you can control the exposure of an impression to the audience by frequency capping, thereby reducing duplication of exposure. Am I correct in assuming that online reach curves are straight lines? Thanks Will

The Media Guru Answers(Thursday, July 18, 2013 ):
No. If reach curves were straight lines, they would not be called "curves."

Under any circumstances, the higher the weigh grows, the more duplication will occur.

Frequency capping does not give the control you imagine. If you place an ad only 10 times, there will be some people exposed 10 times and some only once and many not at all. If you mean that by tracking you limit each user to only 10 exposures, that does nothing to control the number of unique users exposed.

When reach curves are graphed, (Reach vs GRP or Impressions), frequency is a straight line.

To calculate reach, 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


Thursday, October 04, 2012 #8765
Hi I am a mathematician and quite fascinated about Television Ratings, Reach and Market Share. 1.Assuming I have 10 sample homes. 2.Population is of 100 homes. 3.Each of my sample homes has two TV sets. 2.I want to know percentage of homes reached for Channel "A" and "B" in a day part 10:00 PM to 11:00PM. Now Assuming in all homes both the TV sets were ON and Channel "A" was running on TV set1 and Channel "B" was running on TV set2 for all homes in the above mention period. Following the traditional method I get 100% home reach for Channel "A" and 100% home reach for Channel "B" which in my view is incorrect. Could you please suggest the method to calculate reach and Ratings in this kind of scenario. Thank you.

The Media Guru Answers(Thursday, October 04, 2012 ):
Reach is defined as the percentage of the defined population exposed to a campaign or program or media vehicle. Homes exposed divided by population = reach%. For a single unit, reach is the same as rating.

As you have structured your scenario, 100% of homes are "reached" by channel A, which has a 100 rating, and 100% of homes are "reached" by channel B, which has a 100 rating.

It is not clear whether, in your phrase "in all homes both the TV sets were ON," you refer to all home in the sample of 10 or all homes in the population. If you meant all in the population, then there is no question about the 100% reach.

If you meant all homes in the sample of 10, then you need to consider the enormous statistical tolerance of such a uselessly small sample.

Share is completely irrelevant.


Friday, August 10, 2012 #8744
Dear Guru, Can you please help me with such question - we got here average daily GRP 18+ numbers for differnt OOH formats. Average 6*3 billboard =1,86 daily GRP, we are going to buy 20 billboards for month(37,2 GRP per day). Is there any opportunity to calculate DEC with only GRP numbers (total population aged 18+ - 1 500 000)? Is it also possible to calculate reach and frequency for 4 weeks campaign (I've heard about gallop math model - can we use it for our market?) Thanks in advance

The Media Guru Answers(Friday, August 10, 2012 ):
GRP = DEC divided by population

The result is expressed as a percentage; 100 GRP means DEC equal to population size. Without knowing to which market you refer, it is hard to say definitvely whether the Gallup model is appropriate.

At a guess, the Guru would say, "Probably so."


Sunday, March 25, 2012 #8592
What do u mean by duplication ...is it good or bad....learnt that when u calculate reach you have to consider t duplication...say for example if my reach is 30% for publisher a..and 30% for publisher b...then reach is nit 60% but its less...but this is which reach...reach@1 or reach @2+..3+...also u mentioned that duplication happens between medium say same ad in print and tv....but this is an intended campaign called 360communication...then how come duplication is not favarable here.....thks in advance

The Media Guru Answers(Sunday, March 25, 2012 ):
Duplication is neither good nor bad in itself, it is simply a factor of media audiences which must be considered.

We are promarily discussing 1+ reach, but duplication is a factor in all reach calculation beyond single ads.

If your goal is to optimize reach, as in some, but not all campaigns, then you would want to minimize duplication. If your goals specify a minimum frequency to reinforce your message then dupication would be managed differently,

Spreading the campaign across more different publications, programsor genres minimizes duplication. Concentrating within those increases duplication / frequencyand lessens reach.


Tuesday, March 20, 2012 #8585
Hi Guru We are looking to calculate reach, Frequency and GRP points. Ok for example, for our Radio Calculation: We have a GRP points of 40 points(20 x 2 - because ads was play twice) as statistic show that the particular FM had 20% of the total radio audience. The Reach is 60 as we assume that each time the radio ads was played, a new batch of 30% of our target market listen to the 2nd advertisement of our radio. Therefore, we will have a frequency of 0.67 (GRP/Reach = 54/60). However, for magazine we have a total target audience of 1138540. But the readers of the particular magazine that we chosen only had 28,000 readers which is only 2.5% of our target group. How are we supposed to calculate our reach, frequency and GRP points? Please Advise

The Media Guru Answers(Tuesday, March 20, 2012 ):
The only valid number you appear to have is the 2.5% rating for your magazine.

  • GRP is Rating X # ads, the 20% you describe is share, not rating. The reach is definitely not 60. A very crude estimate of reach could be made by random duplication (see past Guru comment here) on the ratings of the ads. Your rating is probably more like 2 - 5%. Even with your figures, if you did have a rating of 20, which would be 20% of the target market for each ad, how could 30% listen to the second ad?
  • Reach can never be greater than GRP, nor greater than 100%
  • Frequency can never be less than 1.0

Print reach calculation is simple for a single ad like such as you describe. Reach = rating (2.5%). GRP = rating (2.5%). Frequency = 1.0. For a schedule of multip[le ads you need a computer with software such as that offered by Telmar or online through eTelmar.

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 17, 2012 #8576
Hi Guru, in your previous answer we mentioned, Reach X frequency = GRP. Ratings X # of units = GRP, etc. Which reach is this , is it reach(1+) or net reach(3+,or 4+).Thanks Guru

The Media Guru Answers(Saturday, March 17, 2012 ):
The reach being referred to here is 1+, or simple, net reach. The Guru would not use the modifier "net" when refering to reach at 3+ or 4+.

Net reach or reach 1+) always has an associated average frequency, which works in this arithmetic. Reach at specific greater exposure levels is not usually reported alongside an average frequncy.

In the typical chain of events, for a planner, the GRP is the first known value, then reach is detemined and finally frequency is calculated.

In reality, the algorithm of simpler models within some software may be based on calculating frequency to calculate reach, but that is just mathematics.


Sunday, December 25, 2011 #8377
Impressions calculate reach

The Media Guru Answers(Sunday, December 25, 2011 ):
Reach is more usually calculated from GRP

Impressions ÷ population (for the same demographic) = GRP

but you really need a computer with software such as that offered by Telmar or online through eTelmar.

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, May 06, 2011 #7869
How do I calculate reach and frequency for print

The Media Guru Answers(Friday, May 06, 2011 ):
You need a computer with software such as that offered by Telmar or online through eTelmar.

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 25, 2011 #7833
How do i calculate reach, if I only have the GRPs and total target population?

The Media Guru Answers(Wednesday, March 02, 2011 ):
Reach is complex calculation. It considers dupication between each advertising occasion on the same vehicle and between occasions on different vehicles.

Realistically, you need software designed for this purpose, or tables prepared from the results of such software comparing GRP to reach results and considering key variables. See 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

Or tables prepared from the results of such software comparing GRP to reach results and considering key variables.

Very crudely, you could estimate by combining the ratings of all your spots, according to Random probabilty. Click here to see past Guru resposes about this.. This would be an overstimate


Thursday, November 04, 2010 #7809
I am currently trying to calculate reach for a truckside advertising campaign.I have traffic volume statistics to use for this purpose. Could you give me some pointers on how, if I required a reach of say 54%,how would I calculate the amount of trucks required for a specific region?

The Media Guru Answers(Saturday, November 06, 2010 ):
You need to know how many different people are exposed to each truck.

You need to know how many trucks are in use and the extent to which they are exposed to the same or different people. You would think about whether the trucks have distinct routes or cross each oother. Then soemhow you would figure out when the number of different people from a given number of trucks equals 54% of the target population.

Any given market, the population size, population distribution and patterns of truck movement are unique. Unless the advertising company has done some studies to actually measure these factors, it is hard to begin to make any estimates.


Thursday, August 05, 2010 #7793
How can i calculate reach & frequency for radio?

The Media Guru Answers(Monday, August 09, 2010 ):
It's a complex calculation and calls for computer support. Our own eTelmar is a great choice.


Tuesday, April 13, 2010 #7775
What is a formula that can be used to calculate reach and frequency in just one newspaper?

The Media Guru Answers(Wednesday, April 14, 2010 ):
If you mean reach and frequency for one insertion in one newspaper, the reach is the daily coverage divided by the relevant population (Metro, DMA, Trading area, etc). The GRP is equal to that and the frequency is 1.0.

If you mean multiple insertions in one newspaper, it is more complex to calculate.

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


Thursday, September 18, 2008 #7602
I have a client who would like us to calculate the combined reach & frequency for a cable, spot radio and traffic radio campaign. Without a media mix program, how can I calculate reach & frequency across these various mediums? Are there standard formulas that I should be using?

The Media Guru Answers(Sunday, September 21, 2008 ):
Click here to see past Guru responses regarding combining reaches.


Friday, June 01, 2007 #7346
How do we calculate Outdoor reach? as per the formula that i have i.e reach = (target audience weight x daily GRP's x no of days in the campaign)/frequency) .. This contradicts my answers if I go only one billboard, while I get a respectable no if I go for several billboards...Again If you can try it out yourself how do you calculate reach only for one billboard?

The Media Guru Answers(Saturday, June 02, 2007 ):
The Guru can't find "number of billboards" in your formula, so the question is confusing.

Otherwise, dividing the cume GRPs by frequency will always be correct math to derive reach. But where did you get the frequency?

Take a look at our own TOPS system for out-of-home planning


Wednesday, May 23, 2007 #7337
In our firm we are using PrintAdex softer and we can not get REACH in print. Please could you tell me how can we calculate reach in print? thank u

The Media Guru Answers(Wednesday, May 23, 2007 ):
Our own eTelmar offers tools for print reach.


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.


Tuesday, September 13, 2005 #7010
I have a client whose target audience consists only of Insurance Brokers. I am planning a print campaign and need to justify it to the owner who wants to know only the ROI. I have one weekly business publication and two trade pubs in three markets. I also only have the circulation numbers and nothing else. What is the best way to calculate reach and frequency with this information? Can I also figure the percentage of awareness from these numbers?

The Media Guru Answers(Saturday, September 17, 2005 ):
In trade publications, circulation tends to be heavy among qualified readers, pass-along is often minimal. A conservative audience estimate is audience = circulation. Again, because of this distibution pattern, issue-to-issue cume is minimal. As far as duplication between titles, random probability is a safe estimate, but may be a bit high.

Reach becomes a maximum measure of awareness; you need to estimate the required frequency which generates awareness as well. Ad Awareness can't exceed reach.


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.


Thursday, May 12, 2005 #6921
Dear Guru thanks you for your response on my previous question and I have another question for you. Please tell me how I should calculate reach in the diary methodology when in the diary’s there is not present question about reach of each program (meaning how many people were watching the selected program in the same time with the interviewers). Until this moment I am making media plans based on the GRP’s level on weekly basis, but I have requests from my clients to make media proposals based on reach and frequency. Is it possible to make reach and frequency media plans when the research methodology is diary, and how to do this? Second question is what is the difference between the reach calculations in the diary and reach calculation in the people meters methodology? Thank you in advance.

The Media Guru Answers(Sunday, May 15, 2005 ):
"Reach" of a program means the average (time period) audience of the program. Diary or meter, it means the same thing, although the method differs. Diaries do not "ask about reach;" reach is a phenomenon of the total sample, not the individual. Diaires require the respondent to record viewing as the measurement period goes on, just as meters record this same behavior electronically, and rating or reach is a calculation conducted by the reasearch vendor from the compilation of diaries' or meters' results. Reach models may be built based on cumes genrated in either methodology.


Thursday, May 15, 2003 #5974
I can use random probability to calculate reach. Is there any way I can create a complete frquency distribution? For instance, Is it correct to add up probabilities for an individual for 4 publications (Say 0.75, 0.75, 0.5 and 0.25) and say that frequency for the person is 2.25?

The Media Guru Answers(Sunday, May 18, 2003 ):
The Guru follows neither your math nor your logic here.

If your example means the the indivisual has a 75% chance of reading the first publication, etc how would that give the person a 2.25 frequency for the 4? You are working with almost unrelated data, not to mention the overstatement of random probability in calculating reach of related media. Further, frequency distribution deals with the numbers of persons who experienced each integral frequency, i.e. how many had one exposure, how many had two exposures. No individual may have a fractional exosure.


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


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


Thursday, January 03, 2002 #4971
Dear Guru - Was there ever a "chart" that enabled media buyers to calculate reach/freq, gross impressions etc for broadcast television planning. I have been explaining to someone that we use programs for this kind of thing, but this person seems to remember using a chart and thinks i should be able to do this manually if he could. I've never heard of it, have you? He would have been planning around 1975. Thanks.

The Media Guru Answers(Thursday, January 03, 2002 ):
Yes, before computers became common in the 80's, when there were just 3 networks, with 90%+ share, no cable, and few independent stations, R&F tables were the way it was done. Every few years, using Nielsen cume studies of actual scehdules, average reaches for various GRP levels were calculated. There might be variables for the number of programs or episodes used. In this way all possibilities for a daypart could be displayed on a single, typed page.

Today, with computers on every desk, 6 broadcast networks amassing only 50% share, dozens of cable options and hundreds of independent stations, accuracy requires computer systems. Such crude tables could be still constructed, but why bother when computers and software are so readily available?

The Guru who was using the charts in the 60's, is happy with his computer today.


Friday, July 06, 2001 #4555
Our agency handles a lot of business to business accounts how would one go about calcualting reach and frequency for each particular business sector ex. one account makes catheters. How would you calculate in various value-added opportunities into reach and frequency like links on a site, direct mail lists etc. Thanks for the great service.

The Media Guru Answers(Friday, July 06, 2001 ):
To calculate reach and frequency two data points are necessary:
Unduplicated audience within the target (sector, in your case) and total population for the target. The media type or unit size are not relevant; reach is pure arithmetic; relative impact and other creative judgements are separate.

It should be basic to estimate the numbers of audience for any media vehicle, site or mailing in your plan. You certainly must have an idea of the size of the sectors you are targeting. The tricky part would be estimating the duplication between advertisements. In the medical field, possibly PERQ has some useful estimates.

Once you add the gross audiecne of all your ads and eloiminate the estimated duplication, you divide by the population to determine reach.


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.


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.


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%


Monday, May 01, 2000 #3434
I am trying to determine how best to manually calculate reach and frequency for Out of Home Media. Would you be able to help and provide me with reach curves and turnover ratios for OOH media. Thank you.

The Media Guru Answers(Tuesday, May 02, 2000 ):
Out-of-home (outdoor poster media) is usually bought in #25, #50 or #100 "showings." These are based on daily effective circulation, or traffic, equal to 25, 50 or 100 GRP per day, respectively.

Within the state of the art, in rough terms, these levels usually mean 4-week reach and frequencies of approximately

  • 80 / 8.8 / 700
  • 87 / 16.1 / 1400 and
  • 92 / 30.4 / 2800.

As should be apparent, there is not much room for fine tuning, nor much reason for considering other GRP levels.


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.


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, 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.


Wednesday, December 02, 1998 #2192
Dear Guru. It is not still clear to me how to measure or calculate reach of the ad campaign using media mix. For example, my ads on TV provided 90% reach, and ads in print reached 25% of the target audience. What is the total reach, frequency of the campaign? What other indexes can we find for such campaign? And my second question is about outdoor advertising. It is essential to measure the effectiveness of the ad campaign comparing awereness and sales before and after the ads placing. But that is somehow the post- campaign analisys and my client would like to see some feagures before the campaign starts (pre-campaign). What indexes (like reach, frequency, GRPs, OTS) can we provide to the discription of the outdoor ad. campaign? Thank You very much.

The Media Guru Answers(Wednesday, December 02, 1998 ):
Reach of a medium in a plan is simply a statistical probability. Further, it is generally thought that each medium overlaps each other medium randomly.

So, in your example, if you consider the reach of each medium as a decimal, the probability of not being exposed to TV is 0.10 and of not being exposed to print is 0.75.

The probability of not being exposed to either one, is therefore 0.10 times 0.75 = 0.075.

Therefore, total reach of the mix is 92.5 (if 0.075 or 7.5% don't see it then 92.5% do see it).

Other basic "counts" for a campaign are impressions (OTS), cost per rating point and cost per thousand impressions.

All of these counts; reach, frequency, GRP, OTS, etc are possible for outdoor, if the research has been done, in your country, to count the audience of the locations used.


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


Saturday, February 22, 1997 #1039
I am trying figure out the best way to calculate reach & frequency for the following:

Television Flight:
4 consecutive weeks (250 TRP's per week)
Then scaling back and running 175 TRP's per week - Every other week for the following 8 weeks.

How do you calculate R&F when your schedule runs on an every other week basis?

The Media Guru Answers(Monday, February 24, 1997 ):
There is no basis for believing that an alternate week schedule of 700 total points (175 per week for 4 of 8 weeks) cumes to a different total than 87.5 grp per week for 8 weeks, as long as the scedules are otherwise identical in numbers of different announcements, and numbers of different episodes of the same programs.

It is true that if the schedules per week of activity were solarge as to exhaust reach potentials, the answer might bedifferent, but this is far below such levels

So the total schedule of the first four weeks at 250, plus the 4alternating weeks can be calculated as if there were lower levelconsecutive weeks.


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.


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. darrylw@conceptus.on.ca

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.



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