Review Manipulation and Filtering on Digital Platforms

Digital platforms strive to filter out consumer reviews that are manipulated, which has become a common and increasingly vexing problem that can take anywhere from days to months to detect. Yet little is known about the consequences of such reviews on product market performance. Using
data from Apple App Store, we examine how the app’s ranking changes when it receives manipulated reviews that are later filtered out by Apple. Our findings reveal that both one-star and five-star manipulated reviews have a significant positive effect on app rankings within a week of posting. The positive effect of one-star manipulated reviews is particularly surprising, as it contradicts
the expected effect of organic negative reviews and the intent behind using such reviews to harm competitors. We also explore how these effects evolve over time, shedding light on the role of filtering policies in mitigating distortions related to review manipulation. Results show that these effects become negative as platforms filter out manipulated reviews, but this process can take as
long as six months to fully materialize. These findings highlight the need for digital platforms to increase their investment to promptly and accurately control review manipulation for the welfare of both businesses and users on the platform. To the best of our knowledge, this study is one of the first to empirically analyze the short-term and long-term effects of manipulated reviews on product
sales, which provides crucial managerial implications for practitioners.