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 it is computed as the product of the percentage of the
audience reached by a campaign times the frequency, i.e., the number of times 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.
For a clearer understanding, 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.
