ZEW Study Shows Inflation of Good Ratings

There has been an inflation in the stars awarded: In recent years, the number of stars for products in online shop reviews has seen an upward trend, even as the quality of these products, as indicated by accompanying review texts, has remained unchanged.

In recent years, the number of stars for products in online shop reviews has seen an upward trend, even as the quality of these products, as indicated by accompanying review texts, has remained unchanged. Consequently, there has been an inflation in the stars awarded. This is the result of a study conducted by researchers from ZEW Mannheim and Stanford University, who analysed over five million online product reviews and compared the content of the text reviews with their corresponding star ratings.

"Both consumers and providers benefit from truthful reviews. Based on ratings, consumers can make online purchasing decisions for suitable products or services. On the other hand, providers can evaluate their offerings on the basis of the feedback they get. In the case of Uber, for example, both drivers and passengers receive ratings," explains co-author Rebecca Janßen, a researcher in ZEW's "Digital Economy" Unit. "However, if star ratings consistently improve over time, even when product quality does not increase, online review systems may fail to fulfill their function of providing new customers with helpful experience reports."