Google’s ad serving algorithm directs more impressions to responsive search ads with higher ad strength ratings, even though lower-rated ads often achieve better conversion rates and lower costs, according to a new global study.
The research by Adalysis indicates that while higher-rated ads received more impressions in 63 percent of cases, they yielded a higher conversion rate in only 45 percent of ad groups, suggesting lower-rated ads converted more effectively in most instances.
Brad Geddes, founder of Adalysis, attributed this discrepancy largely to the practice of “pinning” specific headlines or descriptions within responsive search ads. Pinned ads frequently receive lower ad strength scores from Google but can pre-qualify users, leading to higher conversion rates, Geddes said.
The study also found that lower-rated ads had a lower Cost Per Acquisition (CPA) in 51.5 percent of ad groups. Overall, higher-rated ads exhibited an 11.8 percent higher CPA compared to their lower-rated counterparts.
Google’s reliance on ad strength as a primary factor for determining which ad to display has intensified since 2022, according to the Adalysis report. This increased emphasis on ad strength appears to sometimes conflict with actual performance metrics like conversion rates and CPA.
Ginny Marvin, Google’s Ads Liaison, has previously acknowledged the complexities of ad strength, noting it is a diagnostic tool and not a direct measure of ad performance in all contexts.
Adalysis, an ad management platform, conducted the study by analyzing a significant dataset of Google Ads accounts. Geddes emphasized the importance for advertisers to look beyond Google’s internal scoring system.
The findings suggest that advertisers should not solely rely on Google’s ad strength recommendations but instead focus on their own conversion data and CPA metrics when optimizing responsive search ad campaigns.
Source: Search Engine Journal
