Gross rating point (GRP) is a term used in advertising to measure the size of an audience (or total amount of exposures) reached by a specific media vehicle or schedule during a specific period of time.
It is expressed in terms of the rating of a specific media vehicle (if only one is being used) or the sum of all the ratings of the vehicles included in a media schedule. It includes any audience duplication and is equal to the reach of a media schedule multiplied by the average frequency of the schedule.
The purpose of the GRP metric is to measure impressions in relation to the number of people in the audience for an advertising campaign.
GRPs are the product of the percentage of the audience reached by an advertisement multiplied by the frequency they see it in a given campaign.
GRPs (%) = Reach (%) × Average frequency (#)
Alternatively, GRPs may be calculated in relation to the number of impressions:
GRPs (%) = 100 x Impressions (#) ÷ Defined population (#)
Target Rating Point
A target rating point expresses the same concept and is calculated in the same manner but with regard to a more narrowly defined target audience. For example, a shaving cream brand may be interested in a target audience of adult men. In this case TRPs would be calculated using the reach, frequency, impressions, and population of men age eighteen years and older.
- Farris, Paul W.; Neil T. Bendle; Phillip E. Pfeifer; and David J. Reibstein (2010). Marketing Metrics: The Definitive Guide to Measuring Marketing Performance (Second Edition). Upper Saddle River, New Jersey: Pearson Education, Inc.
- American Marketing Association, AMA Dictionary.
- Common Language in Marketing Project, 2018.