Question:What is a GRP and how is it calculated?

Answer:GRP stands for Gross Rating Point. A standard measure in advertising, it measures advertising impact. You calculate it as a percent of the target market reached multiplied by the exposure frequency. Thus, if you get advertise to 30% of the target market and give them 4 exposures, you would have 120 GRP.

Now, just like most measures, you have to undestand the limitations of GRPs. People like to think of it as a measure of impact, but that is really overstated. Impact should measure sales, this measures exposures (in fact, it's assumed exposures). So you need to be careful in thinking that 120 GRPs really represents something that is real.