News Release

USF research: Stars outweigh numbers in online review ratings battle

A study found consumers view a 3.5-rated product to be higher — and better — when the score is illustrated in shapes like stars, circles and bars, versus numbers

Peer-Reviewed Publication

University of South Florida



Carter Morgan, University of South Florida

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Credit: USF

Media Contact:
John Dudley
(814) 490-3290 (cell)

TAMPA, Fla. (May 7, 2024) – Mathematically speaking, scoring 3.5 out of 5 is the same as receiving three and a half stars on a five-star scale. But visually speaking, the numbers don’t add up.

When it comes to enticing potential consumers to either click on an ad or buy a product, formats matter. Shapes outweigh numbers in the online review ratings battle.

A new study in the Journal of Marketing Research found that consumers view a 3.5-rated product to be higher — and better — when the score is illustrated in shapes like stars, circles and bars, versus numbers.

“Simply changing a rating’s format from numbers to stars increases the perception of the rating as higher,” said Carter Morgan, an assistant professor in the School of Marketing and Innovationin the Muma College of Business, who co-authored the study.

“This study sheds light on how small changes in the presentation of product ratings can have significant effects on consumer behavior in the online marketplace,” he said.

Morgan said this is the first research to compare the presentation of online ratings across distinct formats.

Researchers found that consumers perceived numerical ratings in the 3.5-3.9 range as lower than if that same rating were presented in stars due to left-digit anchoring.

Left-digit bias is a psychological phenomenon where people place more emphasis on the leftmost digit. A consumer’s brain tends to process numbers digit by digit with a focus on the left most digit when interpreting numbers.

For a rating of 3.5, consumers typically focus on the digit 3 instead of the full number 3.5, therefore believing the rating to be lower than it is, Morgan said.

The study’s findings have practical implications for online retailers, marketing managers and website designers and public policy makers.

Researchers recommend using stars, circles, or bars as opposed to numbers in product ratings because shapes can boost a consumer’s likelihood of choosing a product, their intent to buy it, and even their likelihood of clicking on related advertisements.

Consumer advocates and government agencies have pushed to increase transparency for online ratings and reviews.

Public policy makers may want to consider standardizing rating formats so that customers are not unintentionally biased in their decision-making, Morgan said.

The article, “The Power of a Star Rating: Differential Effects of Customer Rating Formats on Magnitude Perceptions and Consumer Reactions,” published online for early access in the Journal of Marketing Research.

Aside from Morgan, the article’s co-authors include Annika Abell and Marisabel Romero, both from the University of Tennessee Knoxville.

Morgan is available to comment on the study findings. To schedule an interview, please contact John Dudley at or 814-490-3290.


About the University of South Florida

The University of South Florida, a high-impact research university dedicated to student success and committed to community engagement, generates an annual economic impact of more than $6 billion. With campuses in Tampa, St. Petersburg and Sarasota-Manatee, USF serves approximately 50,000 students who represent nearly 150 different countries. U.S. News & World Report has ranked USF as one of the nation’s top 50 public universities for five consecutive years, and this year USF earned its highest ranking ever among all universities public or private. In 2023, USF became the first public university in Florida in nearly 40 years to be invited to join the Association of American Universities, a prestigious group of the leading universities in the United States and Canada. Through hundreds of millions of dollars in research activity each year and as one of the top universities in the world for securing new patents, USF is a leader in solving global problems and improving lives. USF is a member of the American Athletic Conference. Learn more at

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