Business Commons^™

The Effect Of Electronic Word Of Mouth On Sales: A Meta-Analytic Review Of Platform, Product, And Metric Factors, Ana Babić Rosario, Francesca Sotgiu, Kristine De Valck, Tammo H. A. Bijmolt

Marketing: Faculty Scholarship

The increasing amount of electronic word of mouth (eWOM) has significantly affected the way consumers make purchase decisions. Empirical studies have established an effect of eWOM on sales but disagree on which online platforms, products, and eWOM metrics moderate this effect. The authors conduct a meta-analysis of 1,532 effect sizes across 96 studies covering 40 platforms and 26 product categories. On average, eWOM is positively correlated with sales (.091), but its effectiveness differs across platform, product, and metric factors. For example, the effectiveness of eWOM on social media platforms is stronger when eWOM receivers can assess their own similarity to …