Wilson Score Ranking

Overview

Wilson Score interval provides a lower confidence bound on the true proportion of positive ratings. Unlike simple averages, it penalizes items with few ratings, preventing a 5/5 review item (1 review) from outranking a 4.8/5 item (1000 reviews). Computes in O(1) per item.

When to Use

Trigger conditions:

• Ranking items by user ratings when review counts vary widely
• Building "top rated" or "best of" lists that are fair to well-reviewed items
• Sorting binary feedback (upvote/downvote) with confidence

When NOT to use:

• For continuous scores (use Bayesian average instead)
• When comparing items with similar sample sizes (simple average suffices)

Algorithm