Unboxing the Causal Effect of Ratings on Product Demand: Evidence from Wayfair.com*
利用断点回归设计，研究发现Wayfair.com上产品评分每提高半星，需求增加5%，该效应由销量驱动而非价格，且对评论多或不知名品牌的产品更强。
Using a regression discontinuity design, I estimate the causal effect of increasing product ratings by half a star on Wayfair.com to be a 5% increase in product demand. Utilizing a transaction‐level dataset, I show that this is driven by an increase in sales, not a price change. This effect is stronger for products with more reviews or sold by lesser‐known brands (and nonexistent for those with no reviews or from popular brands). Also, products with the highest ratings see the largest benefit from having a marginally higher rating. I fail to find reviews affecting repeat purchasers differently than first‐time customers.