Does certainty tone matter? Effects of review certainty, reviewer characteristics, and organizational niche width on review usefulness

Given the proliferation of online review websites—e.g., Yelp.com—that prominently display a large number of online custome0r reviews, scholars have made efforts to investigate what makes a review “useful.” However, there is little research that offers insight into how review content, reviewer characteristics, and review contexts jointly influence review usefulness. We specially examine the role of review certainty on review usefulness. Drawing on dual-process and social influence theories, we examine the interaction effects of review certainty, reviewer popularity, reviewer expertise, and the niche width of a restaurant on review usefulness. In particular, this study focuses on how review certainty interacts with other contextual factors to influence users’ evaluation of the usefulness of online reviews. Utilizing a zero-inflated negative binomial Poisson regression, we empirically tested our hypotheses based on 10,097 reviews on 2,383 restaurants from Yelp.com. Our results indicated that (1) the impact of review certainty on review usefulness decreases with reviewer popularity but does not vary with reviewer expertise and (2) the niche width of a restaurant—as a contextual feature—interacts with review certainty and reviewer characteristics in influencing review usefulness. Theoretically, these findings contribute to online customer review literature and certainty literature, as well as social media research, provide new guidelines for predicting review usefulness, and add new insights into understanding the role of organizational positioning for customer evaluations. In practice, our findings can help online review platforms better understand how to screen and select useful reviews for visitors.