USE STARS ★ NOT NUMBERS FOR RATINGS

Summary from the TLDR Marketing newsletter

Visual product ratings like stars or bars are perceived as higher than number-based ratings, leading to greater purchase intent. In experiments, a 3.7-star rating was judged 25.7% higher and chosen 64% more often than the same number shown numerically. Ads using visual ratings had a 52.6% higher click-through rate than those with numbers. This effect is driven by left-digit bias, which causes people to mentally round down numerical ratings.