Exploring the influence of online reviews and motivating factors on sales: A meta-analytic study and the moderating role of product category

Online reviews, which significantly influence product sales, have been a central research topic in the field of marketing. Meanwhile, some motivating factors related to online retailers have been linked to product sales. While several articles have examined the impact between online reviews and motivating factors on product sales, many of the conclusions drawn are contradictory. From 28 studies focusing on online reviews and sales, this study performs a meta-analysis to analyze the true impacts of six review-related factors (i.e., the number of reviews, star ratings, standard deviation of ratings, helpfulness, review length and sentiment), and two motivating factors (i.e., price discounts and special shipping) on product sales. Meanwhile, this paper also studies how one product-related factor (i.e., product age) and one reviewer-related factor (i.e., reviewer's reputation) influence the relationship between online reviews and product sales. In addition, to study the moderating effect of product category, we divide the selected literature into two subgroups which are search and experience products. The results indicate that only review length and special shipping have no significant impact on product sales, while product category has a valid and specific moderating effect on the relationship between these determinants and sales. The presented conclusions will have important implications for academic research and for future industry practice.