Gross rating points (GRP) is a measure of the impact or intensity of a media plan. GRP is calculated by multiplying a vehicle's rating by the frequency or number of insertions of an advertisement. GRP provides the advertiser with a rough guideline about the chances that a chosen target audience actually sees an ad. Increasing the frequency of an advertisement or increasing the number of vehicles in which the ad is placed improves the odds that a consumer will see the advertisement. An advertisement that appears in each issue of a magazine such as People over a four-week period would be more likely to be seen than an advertisement that appears only once during that four-week period.