GRP data, also known as Gross Rating Point data, is a measurement used in advertising and marketing to determine the reach and frequency of a specific media campaign. It takes into account the total number of individuals or households exposed to an advertisement, as well as the number of times they were exposed to it. This data is crucial in evaluating the effectiveness of a campaign and making informed decisions on future advertising strategies. GRP data is often used in conjunction with other metrics, such as target audience demographics, to provide a comprehensive understanding of the impact of a campaign.