 Hospital mortality funnel plot

A hospital mortality funnel plot places each hospital's observed mortality proportion against its case volume. Under an independent binomial distribution model with common target p, the standard error is $\sqrt{p(1-p)/n_i}$, so uncertainty bands contract as volume grows. This is a provider-performance plot, distinct in purpose and axes from a meta-analysis funnel plot. A signal requires investigation of data quality and patient case mix before drawing a causal conclusion.