Results from Google Ads’ interest-based advertising testing

What we learned

We learned that interest-based audience solutions with privacy-preserving signals showed promise compared to third party cookies. The experiment showed that when using interest-based audience (IBA) solutions with privacy-preserving signals on the display network, Google Display Ads advertiser spending on IBA — as a proxy for scale reached — decreased by 2-7% compared to third-party-cookie-based results. For conversions per dollar, as a proxy for return on investment, the decrease was 1-3%. Finally, we also observed that click-through rates remained within 90% of the status quo. And we observed similar performance for Display & Video 360.

The experiment also suggests that AI-powered optimization solutions can positively impact campaign performance. For example, 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.

These results — while encouraging — should not be considered as an unequivocal indicator of Google’s IBA performance after the third-party cookie deprecation. The current experiment measures the effectiveness of serving interest-based audiences; the results of future experiments including measurement, remarketing, and other use cases may vary.