Research "An empirical study of scale economies in the Chinese Railway System"

An empirical study of scale economies in the Chinese Railway System Although results are not presented here, I have estimated several additional specifications of the basic empirical test. The absence of a positive choice effect does not seem to derive from the particular weighting of the data used here—one might prefer to weight MSAs equally, or by the number of SAT-takers, rather than by their high-school-age populations—nor from the inclusion in the sample of schools with too few SAT-takers to permit accurate estimation of the school mean...