How to interpret your dot: decoding the message of clinical performance indicators

Comparative performance reports continue to proliferate, so it is increasingly important that healthcare workers can interpret the graphically displayed results correctly. This article acquaints readers with key concepts for thinking clearly and critically about such displays: (1) articulating the question a display answers, along with reflecting on questions the display might appear to, but does not, answer; (2) establishing that provider comparisons are made fairly, ever mindful of methodological assumptions and limitations; (3) accounting for systematic differences among performers that are unexplained by specified predictors, that is, random effect methods that yield 'shrunken' estimates; (4) understanding funnel plots used to summarize complex analyses and how one may vary the interrogative focus so that 'outlier' values most likely signal extraordinary performance. Finally, these concepts are given broader context in a view of the ultimate aim of the evaluative enterprise.