What are target rating points (TRPs)?

TRP versus GRP

GRPs are computed against the whole population. TRPs are computed against the audience you actually want.

A campaign delivering 200 GRPs might deliver only 60 TRPs if the placements reach the general public efficiently and the target audience poorly. The first number describes how much advertising ran; the second describes how much of it reached someone who mattered.

For any campaign with a defined audience, TRPs are the more honest figure — which is why media plans that lead with GRPs are worth reading carefully.

How TRPs are used

• Comparing plans that reach the same population with different audience efficiency.
• Setting weight targets against a defined audience rather than against everybody.
• Cross-media comparison, where reach and frequency are the only common currency between television, video and digital.
• Efficiency measurement — cost per TRP is the standard yardstick in television buying.

The limitation both share

Neither GRPs nor TRPs say anything about effect. They measure delivered weight against a population, which is an input rather than an outcome.

A campaign can deliver its target TRPs precisely and change nothing, if the creative does not work or the audience definition was wrong. This is not a criticism of the metric — it was designed to plan delivery, and it does that well — but it is the reason planning metrics and effect measurement have to be kept distinct.

The instrument for effect remains a holdout — see incrementality — regardless of how precisely the weight was delivered.