Why stars
Stars are instantly understood and easy to tap. Scale length affects reliability and preference (Preston & Colman, 2000), and around five points balances discrimination and ease. Ratings and reviews affect sales (Chevalier & Mayzlin, 2006), making them a key decision signal.
The average rating trap
Ratings cluster at the extremes in a J shape (Hu et al., 2009), so averages mislead, and raters may satisfice (Krosnick, 1991). Show review count, a 1–5 distribution bar and recent reviews. Early reviews anchor impressions (anchoring effect) and bad ones loom larger (negativity bias).
Input and prompt timing
Make stars large and spaced for thumbs (Parhi et al., 2006), show selection instantly and allow edits, and add optional reason tags. Apple (n.d.) advises asking at non-disruptive moments, such as after a task, and not too often. State '4.5 out of 5' in text per WCAG 2.2 (W3C, 2023) 1.1.1 and 1.4.1.
FAQ
- Are five stars best?
- No single answer; five is familiar, though thumbs up/down sometimes fits better.
- How to show half stars?
- Use partial stars for averages and also show the exact number.
Sources reviewed: 2026-10-27
References
- Hu, N., Zhang, J., & Pavlou, P. A. (2009). Overcoming the J-shaped distribution of product reviews. Communications of the ACM, 52(10), 144–147. J-shaped review distributions.
- Chevalier, J. A., & Mayzlin, D. (2006). The effect of word of mouth on sales: Online book reviews. Journal of Marketing Research, 43(3), 345–354. Ratings affect sales.
- Preston, C. C., & Colman, A. M. (2000). Optimal number of response categories in rating scales: Reliability, validity, discriminating power, and respondent preferences. Acta Psychologica, 104(1), 1–15. Optimal number of scale points.
- Krosnick, J. A. (1991). Response strategies for coping with the cognitive demands of attitude measures in surveys. Applied Cognitive Psychology, 5(3), 213–236. Satisficing in ratings.
- Apple. (n.d.). Ratings and reviews. Human Interface Guidelines. When to ask for ratings.
- Parhi, P., Karlson, A. K., & Bederson, B. B. (2006). Target size study for one-handed thumb use on small touchscreen devices. In Proceedings of MobileHCI 2006 (pp. 203–210). ACM. Star size and spacing.
- World Wide Web Consortium. (2023). Web Content Accessibility Guidelines (WCAG) 2.2. Criteria 1.1.1 and 1.4.1.