TAMPA, Fla. — Things that should be equal aren’t always equal — that was the takeaway from a recent study co-authored by University of South Florida assistant marketing professor Carter Morgan.

What You Need To Know

  • A study co-authored by USF professor discovered shapes outperform numbers in online ratings 

  • He cites a psychological phenomenon known as "left-digit bias" for why numerical ratings perform worse   

  • For example, he said consumers focus on the "3" in a rating of "3.5" 

Morgan and his colleagues, University of Tennessee professors Annika Abell and Marisabel Romero, discovered that consumers viewed online ratings with star shapes more favorably than ratings with numbers.

For example, people were subconsciously more impressed by a 3 1/2 star rating than they were by a 3.5 rating, even though they should be considered equal.

“What you see isn’t always how you’re processing something,” Morgan said.

Morgan and his co-authors came to their conclusion by using eye trackers available at USF, that monitored where people’s eyes were focused when looking at ratings. Heat maps clearly showed a focus on the fourth star in a 3 1/2 star rating, yet a fixation on the “3” in a “3.5” numerical rating.

Morgan cites “left-digit bias” for why it is happening.

“We can see this left-digit bias with the numbers that we aren’t seeing with the stars,” he said, noting that left-digit bias is also the reason many sellers will sell something for $19.99 instead of $20.

Morgan said he believes shoppers can benefit from knowing this possible bias in how they perceive ratings. He also wondered if there might be a benefit to standardizing the ratings system — either numbers, stars, or some other shape/format.

The article Morgan co-authored can be found posted in the Journal or Marketing Research.