\ Variables: Average Star Ratings FINDING THE SWEET SPOT The optimal star rating varied across product categories. But what is most 4. Five Stars is interesting to note is that in no category was the optimal rating 5.0. “Too Good to be True” Star Ratings’ Impact on Purchase Probability Light Bulbs Natural Hair Care Products 0.6 0 More stars equals more sales, right? It seems fairly intuitive 0.4 -1 that higher ratings would lead to higher sales. Our research 0.2 found that this is true—but only up to a point. -2 0.0 Across product categories, we found that purchase likelihood -0.2 -3 typically peaks at ratings in the 4.0 - 4.7 range, and then 1 2 3 4 5 1 2 3 4 5 Star Rating Star Rating begins to decrease as ratings approach 5.0. Put differently, products with an average star rating in the 4.7 - 5.0 range are Women’s Athletic Shoes Herbal Vitamins less likely to be purchased than those in the 4.2 - 4.7 range. 2 1.0 This suggests that shoppers see ratings at the far end of the 0 0.5 spectrum as “too good to be true.” -2 0.0 -4 -0.5 -1.0 1 2 3 4 5 1 2 3 4 5 Star Rating Star Rating High-end Gifts 0.2 0.0 -0.2 -0.4 Maslowska, E., Malthouse, E.C., and Bernritter, S. (2017), “Too Good to be True: 0 1 2 3 4 5 The Role of Online Reviews’ Features in Probability to Buy.” International Journal of Star Rating Advertising, 36(1) 142-163. 9 \ How Online Reviews Influence Sales \ spiegel.medill.northwestern.edu