Standard control chart practice assumes normality and uses estimated parameters. Because of the extreme quantiles involved, large relative errors result. Here simple corrections are derived to bring such estimated charts under control. As a criterion, suitable exceedance probabilities are used.

Provider profiles are an important component of efforts to improve both healthcare productivity and quality. Risk adjustment is the attempt to account for differences in the risk for specific outcomes of cases in different groups in order to facilitate more meaningful comparisons. The value of provider profiles, whether used internally or released to the public, depends both on adequate risk ad...

Multivariate control chats are generally used in situations where the simultaneous monitoring or control of two or more related quality characteristics is necessary. In most processes in the real world, distribution of the process characteristics are unknown or at least non-normal, so the non-parametric or distribution-free charts are desirable. Most non-parametric statistical process-control t...