In this talk, Andreas Bayerl (Erasmus School of Economics) discusses to what extent we can trust online reviews. He presents recent research on how behavioral patterns influence online reviews, focusing on when reviews are written and who writes them. The discussion draws on the paper “The Weekend Effect in Online Reviews” (Journal of Marketing Research, 2026, Andreas Bayerl et al.), available at https://journals.sagepub.com/doi/10.1... , which shows how review behavior systematically differs on weekends, as well as “The Gender Rating Gap in Online Reviews” (Nature Human Behaviour, 2025, Andreas Bayerl et al.), available at https://doi.org/10.1038/s41562-024-02... , which documents consistent differences in ratings between men and women. Together, these findings highlight how contextual and demographic factors shape online ratings, with important implications for platforms, businesses, and AI systems relying on user-generated content.