Finally, a 2-year window width was chosen and therefore four overlapping windows were analyzed over the 5-year study period. The narrow window width was decided since it provides the minimum common ground that allows the year-to-year efficiency comparisons without the possible distortion that would have been imposed if a wider one had been chosen. At the same time, the 2-year width is considered sufficiently large -as far as the discrimination of the method when applied on small groups is concerned—since, it doubles the number of DMUs in each window. It is evident that the choice of a wider window could not be justified –especially within the years of the financial crisis of the country that are characterized by substantial changes in the health care sector affecting, among others, the applied technology. Thus, a wider window would most likely have led to unfair or non-realistic comparisons among hospitals in distant apart years.