Online book reviews are, on average, overwhelmingly positive and have a significant impact on individual book sales. That’s according to a 2006 study by Yale professors Judith A. Chevalier and Dina Mayzlin published in the Journal of Marketing Research. The study focused on the effect of word of mouth on online book sales by examining reviews on both Amazon’s and Barnes & Noble’s websites.
Other findings include:
- Reviews are overwhelmingly positive on both sites (though Amazon has more and longer reviews)
- An improvement in a book’s reviews leads to an increase in relative sales at that site
- For most samples in the study, the impact of one-star reviews is greater than the impact of five-star reviews
- Customers read review text rather than relying solely on summary statistics
