A comparison of public and private schools in Spain using robust nonparametric frontier methods

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The main conclusion that can be drawn from our analysis is that state subsidized private schools are more efficient, although the estimated inefficiency attributable to students is similar in both public and private schools. Actually, the final decomposition of inefficiency allows us to detect that the effect attributable to the school type is almost inexistent, while peer effect and school effect have a greater impact on results, especially in the subsample of public schools.
This result implies that a significant proportion of inefficiency in public schools depends on the characteristics of students enrolled. Those divergences can be explained because students are not randomly distributed between both types of schools, since students with a lower socioeconomic status are prone to be enrolled in public schools due to the higher costs that would entail to attend state subsidized schools.