Out-of-home advertisements are a very effective marketing medium, but how do you quantify the impact of traditional media ads? The industry developed a system to determine an ad’s effectiveness. Today’s blog post will give a quick and succinct explanation of both GRP and TRP.
The first term we need to define is impression. In OOH, impressions are the number of times people are likely to notice an OOH ad. How are these impressions determined? In the OOH industry, the standard for measuring is Geopath. Geopath is a “not-for-profit organization governed by a tripartite board comprised of advertisers, agencies, and media companies.” They use a variety of means to provide the most accurate impression data related to OOH. Once we have the impression data, we can accurately figure out the GRP.
GRP (Gross Rating Point)
GRP, or gross rating points, are a standard measure in advertising used to measure exposure. GRP is the total number of impressions delivered by an ad schedule expressed as a percentage of a market population. In other words, it’s all adults aged 18+. It refers to the percent of the total viewing audience reached multiplied by the exposure frequency. This score is commonly considered to be the primary analytic currency for OOH, but it is also used when planning and buying other types of media. For example, GRP would be used when promoting the upcoming census since they’re trying to reach everyone.
The formula used to calculate the GRP is:
(Reach (% of Audience Reached) × Frequency (# of ad impressions)) × 100
So if 30 percent of the viewing audience sees your billboard 4 times, that ad would have a GRP of 120 ((.3 × 4) × 100).
TRP (Target Rating Point)
Using GRP works well when you’re trying to reach all adults 18+, but in cases where your target is more narrow, it may be more valuable to use TRP. TRP, or Target Rating Point, enables you to determine the number of GRP’s achieved by an advertisement among targeted individuals within the larger viewing population. The calculation is actually rather simple.
The formula used to calculate the TRP is:
GRP × Target Audience as a Percent of Entire Viewing Audience
Going off the earlier example, assume you are targeting males ages 18-25. If you know that this demographic makes up 35 percent of your entire viewing audience your new TRP would be 42 (120 × 35).
That’s all there is to it! Figuring out GRP and TRP isn’t all that scary, after all. We also have tools that can easily calculate TRP and GRP for you. Want to learn more? Feel free to request a demo.
