For the past couple of years, Target and other retailers have encouraged advertisers to use incrementality to measure their retail campaigns. Incrementality is a metric that aims to determine the sales revenue generated by a campaign versus sales that would have happened without showing the ad, often comparing sales across test-and-control groups.

During an event for advertisers in New York on Tuesday, Shawn McGahee, senior director of performance and insights for Roundel, said that only 8% of Roundel’s advertisers are using incrementality measurement as the primary performance metric for their business.