The K index: a proxy measure of health care quality.

An index of health care quality is described that requires data on "sentinel health events"--unnecessary death and disability caused by specific ICDA-coded conditions on which medical agreement can be reached about avoidability of negative outcomes. The proposed index combines measures of incidence, severity, and concentration of sentinel health events in communities and compares the measures with mean values for a group of normative communities, to arrive at index values that are distributed as X2 for a group of communities with regard to the mean health conditions experienced by the normative communities. Calculation of the index is illustrated with hypothetical data, and problems of selecting normative communities are discussed.