“…Finally, in our third DEA model we used 1 minus the average hospital mortality rate per year, which represents an index variable. Syrjänen (2004) dies which, however, as mentioned earlier, have certain methodological limitations. Among the control variables, market concentration (HHI) and hospital size (BEDS) were important exogenous market effects, and the regression results revealed a significant positive association with efficiency in all three models (P0.001).…”