A Cross-national Comparison of Click-through Rates for AI Overview Keywords

Abstract

The growth of AI Overviews in Google Search has prompted questions about whether searcher click behaviour varies across national markets. Understanding cross-national click-through rate (CTR) differences is critical for global ecommerce brands managing search engine optimisation (SEO) strategies across multiple regions. This study examines whether CTR for AI Overview keywords differ significantly between US and UK searchers, after controlling for keyword difficulty, keyword intent, and keyword competition. A cross-sectional analysis was conducted on 1,303 keyword-level observations drawn from 18 ecommerce websites tracked across both markets during the month of December 2025. The ANCOVA regression analysis documented that US keywords exhibited significantly higher AI overview CTR compared to UK keywords (B = 0.272, p < .001, partial η² = .033). navigational and transactional intent keywords also yielded significantly higher CTR than informational keywords. Keyword difficulty and competition were not significant predictors. US searchers demonstrate consistently higher CTR for AI Overview keywords than their UK counterparts, independent of keyword characteristics. These findings have implications for how global ecommerce brands should interpret and benchmark CTR across markets.