Gross Rating Points

The metric commonly used for weight of advertising is called Gross Rating Point or GRP in short. It measures quantum in terms of the size of the audience reached, and is computed as the product of the percentage of the audience reached by a campaign times the frequency they see it. This is the same as the sum of the % viewership of the programmes where the campaign is aired.

For example, if in a particular week a brand’s advertisement is aired five times over different programmes, and the viewership across these programmes is 40%, 25%, 15%, 30% and 5%, then the GRP for that week is 115 (40 + 25 + 15 + 30 + 5).

Share of Voice is the brand’s advertising weight (GRP) expressed as a percentage of relevant market (category or segment). Share of voice may also be expressed in terms of share of advertising expenditure.

It is pertinent to elaborate how viewership is defined as this greatly impacts the size of audience and, consequently, GRP. The industry norm for TV (and radio) is the average minute audience (AMA), and this is defined as the average number of individuals or (homes or target group) viewing a TV channel (or listening to a radio station), during an average minute measured over the programme’s duration.