When reviews tell the truth: the power of verified purchase ratings

Purpose Grounded in source credibility and trust-transfer theories, this study investigates how a Verified Purchase Scheme (VPS) enhances the sales’ predictiveness of ratings’ valence and reshapes reviewer behavior, while identifying situational uncertainty as a crucial moderator for eWOM effectiveness. Design/methodology/approach We employ a multi-method design combining empirical analysis of movie box-office data and reviews with a controlled experiment. This multi-stage approach compares behavioral shifts before and after VPS adoption and utilizes a randomized experiment to identify the underlying credibility mechanisms in high-uncertainty environments. Findings Results show that verified valence predicts sales’ post-VPS adoption, as verification leads to more measured ratings through increased accountability. Furthermore, experimental evidence demonstrates that the impact of a VPS is significantly amplified under situational uncertainty, where the verified badge serves as a critical diagnostic anchor. Originality/value This research advances interactive marketing by conceptualizing a VPS as a platform-governance mechanism that transfers trust from transactions to review sources. We specify when and why valence predicts sales by establishing situational uncertainty as a vital boundary condition for the informational value of ratings.