How wide is the uncertainty around that win rate?
A reported win rate is a measurement, not the true rate. The Wilson interval gives the range of values that are consistent with the data at a stated confidence level. The tighter the range, the more the sample supports the point estimate. Slide the controls below to explore.
Wilson behaves well at small N and at proportions near 0 or 1, where the more familiar Wald (normal-approximation) interval becomes misleading. 95% is the conventional confidence level; this tool uses it throughout.