From claims to conversions: exploring sustainable advertising, brand trust and review dynamics in online green purchases

Purpose This study investigated the negative effects of perceived inconsistency in corporate sustainability claims (sustainability schema inconsistency) on consumers. The moderating roles of brand signals and online reviews and psychological mechanisms underlying the negative effects of such inconsistency, were also explored. Design/methodology/approach Experiment 1 used a one-factor within-subjects design to examine whether sustainability schema inconsistency negatively affects consumer responses. Experiment 2 used a one-factor (well-known versus unfamiliar brand) between-subjects design to determine whether brand signals mitigate these negative effects. Experiment 3 used a 2 (brand: well-known versus unfamiliar) × 3 (online reviews: star ratings, review volume and review content) between-subjects design to examine the main effects and interaction of brand signals and online reviews. Experiments 2 and 3 investigated brand trust's mediating role in this relationship. Findings (1) Inconsistent sustainability messages significantly negatively affect consumer attitudes toward products, willingness to recommend, purchase intentions and brand satisfaction. (2) Brand trust is a key mediator, strong brand signals mitigate schema inconsistency's negative effects and negative emotions have limited influence. (3) Online review type moderates these effects: review quantity and content amplify negative responses more than star ratings, particularly for lesser-known brands. These results highlight how schema consistency, brand reputation and user-generated content interact to shape green consumer behavior. Practical implications The findings underscore the importance for brands, particularly well-known ones, to maintain consistency in sustainability communication. Inconsistent messages can backfire and diminish consumer trust, making it crucial for companies to align their marketing claims with actual practices to sustain credibility and drive green product adoption. Originality/value This study confirms that inconsistency in corporate sustainability messaging negatively affects consumers and demonstrates the protective role of brand signals. It identifies how consumer-generated online reviews contribute to perceived schema inconsistency, supporting the brand trust’s mediating role in shaping consumer reactions.