Few developing countries participate in external educational evaluations. Information gaps on education quality make it imperative to expand such evaluations. Furthermore, international comparability across different evaluations should be improved. In addition, data from evaluations must be combined with data on access or coverage. Finally, educational evaluations reveal social inequalities; socioeconomic status has a systematic influence on educational outcomes, but social gradients vary over countries. Resources alone cannot explain massive performance gaps between developing and developed countries. Large efficiency improvements must occur in classrooms and schools. The need is not for "league tables," but for data that allow countries to judge the appropriateness of their policies and strategies in an international context. Efficient and targeted application of resources and policies to improve education in developing countries requires information on system performance, inequalities, progress and stagnation. International evaluations should be expanded to more countries, should be better anchored and comparable, and should be demystified. Too little international educational evaluation is the enemy of progress.