Pros & Cons

In online reviews, when are four stars better than five?

When the five-star reviewer dilutes a highest-possible rating by noting a few negatives. That perceived inconsistency is enough to render an “excellent” rating less convincing than a merely “good” rating that is deemed more credible.

This according to new research by Ann Schlosser, an associate professor of marketing at the University of Washington Foster School of Business. In one of the first studies to consider both quantitative (numerical ratings) and qualitative (written arguments) dimensions of peer reviews, Schlosser finds that consumers are suspicious when a highest rating doesn’t jibe with its less-than-perfect written explanation.

“In a peer review, consumers want to get a fuller picture of the pros and cons of a product,” Schlosser says. “But, ironically, presenting a product’s pros and cons is not always more helpful, credible and persuasive—specifically when there is a perceived inconsistency between a reviewer’s rating and supporting arguments.”

The cost of credibility

Peer reviews are increasingly important to product sales, on the Internet and even in stores. Recent studies have shown that more than half of consumers prefer sites with peer reviews and 98 percent of online shoppers report reading peer reviews before making a purchase.

For online retailers, independent peer reviews are also thought to enhance credibility—the more balanced the better.

But, according to Schlosser, credibility has two components: ability and willingness to tell the truth.

Willingness is largely a question of a retailer’s sincerity. And hosting unvarnished, “warts-and-all” product reviews that are composed by actual customers has been shown to boost this aspect of credibility.

“In general,” Schlosser says, “people do trust peer reviews more than advertisements or sales associates. But being credible is thought to be synonymous with being trustworthy—willing to tell the truth. The other aspect of credibility is expertise, ability to tell the truth. That seems to be the driving force for whether people actually use this information.”

Consistently inconsistent

The ability of reviewers to provide useful, credible information comes into question when product reviews include both overall ratings (often denoted in stars) and written explanations (either freeform or organized into pros and cons).

This is the trend in online retail sites. Many offer reviewers the opportunity to both assign a numerical “score” and to call out their likes and dislikes about a product. It’s the conformity—or contradiction—of these two review elements that came under Schlosser’s scrutiny in the study.

“People,” she says, “are a lot less consistent than we expect them to be.”

So it’s perfectly normal that a reviewer might give a pair of running shoes, for instance, a perfect five-star rating while also pointing out that the shoes were painfully slow to arrive. The extreme positives—perfect fit, durable, look great—may be enough for the reviewer to overlook an imperfect buying experience when issuing an overall rating.

But that’s not how shoe-shoppers see it.

“We expect people to be consistent,” Schlosser says. “If you give something the highest rating, then why are you telling me things you didn’t like about it? You expect extremely favorable raters to present only pros and the moderately favorable or unfavorable raters to present pros and cons.”

Schlosser found that prospective buyers find this kind of review—perfection… with caveats—less persuasive than a lukewarm rating supported by pros and cons. This more moderate rating is seen as consistent and, thus, credible.

“People are more persuaded by reviews they perceived as consistent than reviews they perceive as inconsistent,” she adds.

Improve peer reviews online

What’s an ecommerce retailor to do? On one hand, encouraging peer reviewers to express both positive and negative reactions can lend credibility to a site, product or brand. On the other, it can lead consumers to remove the most positive reviews from consideration.

Schlosser suggests that retail or aggregation sites could direct reviewers to complete their written review before selecting an overall rating score. They could merely offer, rather than encourage, the listing of cons alongside pros. They could use a fractional rating system that allows a more nuanced final verdict (4.3 rather than 5 stars). Or they could ask viewers to rate products on a variety of dimensions that average to an overall rating.

“The best strategy may be to instruct reviewers to be consistent,” she adds, “to explain what they liked if they give a product the highest rating possible, and to include what they disliked only if they have a moderately favorable rating.”

“Can including pros and cons increase the helpfulness and persuasiveness of online reviews? The interactive effects of ratings and arguments,” is published in the July 2011 Journal of Consumer Psychology.