The Scale Effect: How Rating Scales Affect Product Evaluation
(A2020-64499)

AUTHORS

Rahil Hosseini, Pompeu Fabra University; Gaël Le Mens, Pompeu Fabra University

KEYWORDS

Rating; Scale; Evaluation

ABSTRACT

People frequently consult online ratings before purchasing goods or services. Review websites provide ratings on different scales. Amazon relies on a 5-star rating scale, Trustpilot on a 0-to-10 TrustScore, and Consumer Reports on a 100-point scale. We study how people combine pairs of ratings of the same product provided on different scales into an overall valuation of the product. Based on prior research on numerosity, we predicted that ratings provided on larger scales would affect valuation and purchase intentions more strongly than ratings provided on smaller scales. In four studies (N = 2560) we found support for this prediction. We call this phenomenon the scale effect.