User Reviews Variance, Critic Reviews Variance, and Product Sales: An Exploration of Customer Breadth and Depth Effects

Online user reviews constitute a new element of the marketing communication mix that can significantly affect product sales. A general consensus holds that positive user reviews valence benefits product sales, yet the effect of variance is less intuitive and current findings are mixed. We propose that user reviews variance actually constitutes a double-edged sword that can either hurt or help product sales, depending on the variance of critic reviews and other quality signals. Three complementary studies in multiple industries (movies, digital cameras, and books) with multiple methods (secondary data analysis and behavioral experiment) reveal three key insights in this setting. First, after recognizing a high variance in user reviews, many potential buyers may simply exclude the focal product from their consideration sets for fear that it does not match their needs and preferences, which is termed the customer breadth effect. Second, high user reviews variance, in combination with high critic reviews variance, can elicit a sense of uniqueness and thus enhance purchase intentions of some consumers, which is termed the customer depth effect. Third, quality signals (e.g., product cost and product extension) can strengthen the positive customer depth effect. The overall effects of user reviews variance, therefore, can be negative, insignificant, or even positive. These findings have important theoretical and managerial implications.