Methods of Calculation

Calculator...A Media pan has to be based on reliable information. This is especially true when you need to calculate audited data. Using these calculators you can impose a discipline to your buying and plannng process. In turn create more confidence and conviction in your plan.

Calculating GRPs, Reach and Frequency
Calculating Circulation Delivery and Cost Data

Calculating GRP's, Reach and Frequency

Target Audience Weights
Each of the three methods used to calculate out of home reach and frequency produces an estimate of total audience reach. Advertisers and agencies usually focus communications efforts on targeted sub-sets of the total population that are defined by demographic characteristics (age, gender, etc.) or geography or even consumer behavior. Target Audience Weights are used to factor reach and frequency results to produce an estimate of the delivery of target sub-groups.
The Target Audience Weights take into account the propensity of each group within the Adult population to be exposed to out of home media.

Target Audience Weight	=
(1.0 for Adults 18+)
Panels	=
Daily Effective Circulation (DEC)	=
Market Population	=
Days	=

Daily Gross Rating Points (GRP's)	=

For Posters:
Poster Frequency	=
Poster Reach	=	%

For Rotary Bulletins:
Rotary Frequency	=
Rotary Reach	=	%

For Permanent Bulletins:
Bulletin Frequency	=
Bulletin Reach	=	%

Target Audience Weights

Demographic	Total	Men	Women
Adults 18+	1.00	1.14	0.88
18-24	1.01	1.20	0.84
18-34	1.04	1.17	0.91
18-49	1.09	1.20	0.98
25-34	1.05	1.14	0.95
25-54	1.10	1.20	1.00
35-44	1.15	1.23	1.07
35-49	1.14	1.24	1.05
45-54	1.10	1.24	0.97
55-64	0.98	1.16	0.82
25+	1.00	1.13	0.88
35+	0.98	1.12	0.86
50+	0.84	1.00	0.70
65+	0.65	0.79	0.55

Income:
HHI $50,000+	1.16	1.14	1.18
HHI $60,000+	1.19	1.16	1.19
HHI $75,000+	1.21	1.19	1.22

Source: Nationwide Personal Transportation Study
* The benchmark of adults 18+ is always represented as 1.00

The Gallop Math Model
The Gallop Math Model is an arithmetic formula that has been in use for 40+ years in the out of home industry. It assumes a constant reach across a campaign period equal to the average daily circulation of a schedule of locations. See Formulas below.

GRP (Gross Rating Point)
A method for measuring an audience with duplicated circulation over a period of time. GRP levels for out of home media refer to daily circulation expressed over a week. One rating point represents the circulation equal to 1% of a market's population.

The arithmetic formula for calculating Daily GRP's = Average DEC / Market Population

Reach
The percentage of a target audience population which has been exposed (had an opportunity to see) an advertising message at least once. The reach (unduplicated audience) is usually calculated for a schedule of locations (advertisements) over a period of time (week, month, quarter, campaign).

The arithmetic formula for calculating Reach = (Daily GRP's x TAW x No. of Days) / Frequency

Frequency
The average number of times, during a specified reach period that an individual has the opportunity to see an advertising message. An out of home reach estimate should reflect audience accumulation over time in the same way that a broadcast or print reach estimate reflects audience accumulation over time.

The arithmetic formula for calculating Frequency = (Daily GRP's x TAW x No. of Days) / 100 [Posters(+2), Rotary Bulletins (+4), Permanent Bulletins (+6)]

Calculating Circulation Delivery and Cost Data

Calculating Circulation Delivery
Posters, bulletins and bus shelters are now sold on the basis of Gross Rating Points. The term Gross Rating Points (also called TRPs or Target Rating Points), refers to the total number of impressions in duplicated exposures delivered by a media schedule expressed as a percentage of a market population. A single rating point represents one percent of a population group. For example, 700 weekly GRPs, means that the panels in an outdoor program deliver weekly circulation equal to 100% of the market's adult population. Thus, Gross Rating Points provide a convenient way to communicate and translate audience coverage information in terms that advertisers understand.
Using the TAB Plant Operator Statements, the buyer can calculate GRPs and circulation delivery using the following formulas:

A 700 Weekly GRP Program Allotment = Market Population (Adult 18+) / Average DEC Per Panel and round up.
Daily Gross Impressions = No. of Panels in Allotment X Average DEC Per Panel
Weekly Gross Impressions = Daily Gross Impressions X 7

Use this calculator to determine your program's circulation delivery. The data entered is an example using 30 Sheet Posters, a market population of 350,000 and a Average Per Panel DEC of 20,000. Note, in this example, the 700 GRP program actually delivers slightly more than 100% of the Adults 18+ market population. To determine your program's circulation delivery, replace the data fields with your information.

Adult 18+ Population	=
Average Per Panel DEC	=
700 Weekly GRP Program	=
Daily Gross Impressions	=
Weekly Gross Impressions	=

Calculating CPMs (Cost Per Thousand)
Using the circulation delivery information, comparative analysis can be made market-to-market or plant operator against plant operator within any market. This can assist in the estimation of overall out of home media costs.
CPM (Cost per Thousand) refers to the cost of reaching one thousand advertising exposure opportunities in a market. Advertisers use CPMs to compare the efficiencies of media types and schedules.

Gross Impressions = Average Per Panel DEC x Number of Days / 1000
CPM = Media Cost / Gross Impressions

Use this calculator to determine your program's CPMs. The data entered is an example using 30 Sheet Posters with an average Per Panel DEC of 20,000 and a cost per panel of $500.00. To determine your CPMs, replace the data fields with your information.

Average Per Panel DEC	=
Number of days	=
Gross Impressions	=		M
Cost Per Panel	=	$
CPM	=	$

Calculating CPP (Cost Per Rating Point)
To calculate a CPP (Cost Per Point), determine the circulation equivalent of one rating point (1% of the market's population), then divide the monthly per panel circulation by that number to determine the number of rating points delivered by one panel per month. Finally, divide the per panel rate by the resulting number of points to determine the CPP.

One Rating Point = Market Population x 1%
Number of Rating Points Per Panel = Average Per Panel DEC x Number of Days / One Rating Point
CPP = Cost Per Panel / Number of Rating Points Per Panel

The data entered is an example using 30 Sheet Posters with an average Per Panel DEC of 20,000 and a cost per panel of $500.00. The example city has a population of 350,000. To determine your CPP, replace the data fields with your information.

Population	=
One Rating Point	=
Average DEC	=
Number of Days	=
Cost Per Panel	=	$
Rating Points Per Panel	=
CPP	=

Source: Planning Out of Home Media 2001 Edition