“…The model has the following form: We are aware that our methodology does not allow us to control the endogeneity previously mentioned that could exist between the turnout and the institutional efficiency, so that the estimate of the possible effect can only reflect a non‐causal relationship. Although Amsler, Prokhorov, and Schmidt () and Kutlu, Tran, and Tsionas () have developed econometric procedures that allow environmental variables to be endogenous in the sense that they are correlated with the specific inefficiency component, neither of these studies solved this problem in Battese and Coelli's () stochastic frontier model in a single step, which is the basis upon which we developed all the theoretical considerations that we have assumed.…”