\ Prompted vs. Unprompted Reviews 1. Reviews from Verified Buyers AVERAGE STAR RATING: Have Higher Ratings VERIFIED BUYERS VS. ANONYMOUS REVIEWERS We found that reviews from verified buyers are substantially 70 Anonymous Consumer more positive than reviews written by anonymous sources. 60 Verified Buyer The average star rating for reviews from verified buyers is 50 4.34, compared to an average star rating of 3.89 for reviews e written by anonymous reviewers. In addition, reviews from g 40 a t verified buyers contain a higher percentage of 5-star ratings, n rce30 while reviews from anonymous reviewers have a larger e percentage of 1-star ratings. P 20 These findings are consistent with the theory that people who 10 are self-motivated to write a review have more extreme, and often more negative reviews. We explore this selection bias in 0 1 2 3 4 5 more detail later in the report. Rating Verified buyers are more likely to give four- or five-star ratings than anonymous reviewers are. Conversely, anonymous buyers are significantly more likely to give one- and two-star reviews. Askalidis, Y., Kim, S.J., and Malthouse E.C. (2017), “Understanding and Overcoming Biases in Customer Reviews.” Decision Support Systems. 97 (May 2017), 23-30. 14 \ How Online Reviews Influence Sales \ spiegel.medill.northwestern.edu