Google has detailed the test results of how interest-based audience targeting solutions will perform in a world without third-party cookies.

The experiment was conducted on Google Ads and Display and Video 360 in the first quarter of this year. It includes affinity, in-market, custom audiences and demographic segments on Google’s display network, using a combination of privacy-preserving signals. These signals included contextual information, the Topics API from Google’s Privacy Sandbox and first-party identifiers, such as IDs provided by publishers. The research did not compare the performance of third-party cookies to the Topics API alone, but rather a broader suite of signals available in a privacy-first world.

The experiment was conducted on a share of Chrome traffic in two parts. One arm used third-party cookies and another replaced third-party cookies with a combination of privacy preserving signals for IBA solutions. Third-party cookies were maintained for measurement and remarketing.

The results indicated that interest-based solutions with privacy-preserving signals showed promise compared to third-party cookies. The experiment showed that using interest-based audience solutions with privacy-preserving signals on the display network was more cost efficient. Advertiser spending decreased by 2% to 7% compared to third-party cookie results. The test also used conversions per dollar as a proxy for ROI, where the decrease was 1% to 3%. Click-through rates remained within 90% of the status quo. Similar performance was observed for Display and Video 360.

In addition, Google reports that campaigns using optimized targeting or maximize conversions bid strategies were less impacted by the removal of third-party cookies, indicating that machine learning can play a significant role in driving results.

Google cautions that while results are encouraging, they should not be considered an unequivocal indicator of Google’s interest-based audience solutions performance after the third-party cookie deprecation.

Google plans to continue to iterate and run more rounds of testing in consultation with the Competition and Markets Authority in the U.K. It will continue to provide regular feedback to Chrome and publish findings to the broader industry.

Later this year, Google will release the findings of similar experiments for remarketing and conversion measurement.