Fairness in resource allocation is not only important for equity in education, it is also related to the performance of the education system as a whole. In these systems, there are smaller differences between higher-performing and lower-performing schools in principals' reports on teacher shortage, the adequacy of educational resources and physical infrastructure, and smaller differences in average mathematics learning time between schools with more advantaged and those with more disadvantaged students. In these countries, principals in disadvantaged schools tended to report that their schools had adequate educational resources as much as, if not more than, principals in advantaged schools reported. Scarce resources tend to be more concentrated in advantaged schools, and disadvantaged schools tend to suffer from inadequacy or shortage of resources.