Ads without cookies represent 52% less revenue for the publishers; Google finds

Google last month shared an internal study testing how the presence of a cookie affected programmatic revenue. The study concludes that traffic for which there was no cookie present yielded an average of 52 percent less revenue for the publisher than traffic for which there was a cookie present.

The study was based on an analysis of a randomly selected fraction of traffic on each of the 500 largest Google Ad Manager publishers globally. Lower revenue for traffic without a cookie was consistent for publishers across verticals. Google says the lower revenue was especially notable for publishers in the news vertical.

For the news publishers in the studied group, traffic for which there was no cookie present yielded an average of 62 percent less revenue than traffic for which there was a cookie present.

Deepak Ravichandran, Principal Engineer at Google Display Ads, and Nitish Korula, Senior Staff Research Scientist at Google Ad Manager wrote that removing third-party cookies could have second-order effects on publishers:

1. Decreased spend by their advertising clients as a result of lower return on investment from non-personalized ads and moving budgets to different channels, and;
2. Increased overhead costs as a result of publishers having to adjust their business models when third-party cookies are disabled.

Google also found that users expressed greater dissatisfaction with non-personalized ads because they were not interested in what the ads were showing them. Users can stop seeing an ad by clicking on an “X” that appears on a display ad to close the ad. Google saw a 21% increase in user clicks to close an ad by the treatment group (who encountered non-personalized ads). When prompted with a list of reasons they wanted to stop seeing an ad, there was a 21% increase in user clicks on the reason “Not interested in this ad” and a 29% increase in user clicks on the reason “Seen this ad multiple times.”