Claims-based Indicators of Surgical Site Infection. Graphical display of the hospitals serving UnitedHealth Group members which are in the top quartile of percentage surgical site infection indicators following a cardiac procedure. Hospitals are ranked by their odds ratio compared to a hypothetical control hospital with the median percentage of SSI indicators from among the lowest quartile of hospitals. Odds ratios were derived from a multivariate model controlling for insurer type, sex, chronic disease score, and epoch (see text). Unadjusted percentages of SSI indicators are also shown for each hospital.