Persuasion in Moderation: When four-star reviews are better than five

An avalanche of five-star reviews for a restaurant, a product, or a service might seem to be more persuasive than a single less-than-perfect review. But a recent paper published in the Journal of Consumer Research by Questrom marketing professor Daniella Kupor and Stanford co-author Zakary Tormala suggests that this might not be the case.

In a sea of five-star reviews, a single four-star review might actually be the most persuasive one of all—and lead to more sales.

In the article, “When moderation fosters persuasion: The persuasive power of deviatory reviews,” Kupor and Tormala shared the results of eight distinct experiments that illustrate how reviews that deviate from an extremely good or extremely bad “default score” are the ones that consumers tend to rely on most heavily when making their decisions.

Mining the purchasing decisions and attitudes of more than a thousand study participants for products and services ranging from granola bars to ride-sharing services, the pair found remarkable consistency in people’s views. Against a backdrop of nearly uniform (and brief) extremely positive reviews, consumers typically rated the more moderate positive reviews as the most helpful—and were more compelled to select the item or service as a result of the tempered responses. The reverse was also true: when the reviews were almost universally terrible, it was the more moderate negative reviews that convinced consumers not to buy, rather than the extremely negative ones.

Why would a single moderate review be more potent than dozens with more extreme ratings? The pair’s data suggests that simply straying from popular opinion has an impact. “We are more likely to be persuaded by reviews that deviate from the norm because these deviatory reviews are believed to be more thoughtful, and thus more accurate,” says Kupor. “That enhances their persuasive impact.”

Such findings can help companies decide how to leverage their most powerful reviews—and help consumers understand what’s driving their own decisions. “Many consumers look at multiple reviews when deciding which products to buy, so illuminating the factors that lead some reviews to have greater persuasive impact than others is important,” Kupor says. “Being aware that we tend to be more persuaded by deviatory reviews gives us greater insight into how we make decisions.”

Read the complete article on Journal of Consumer Research.

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