Building upon several decades of thought about human capital – and centuries of general attention to education in the more advanced countries – it is natural to believe that a productive development strategy would be to raise the schooling levels of the population. And, indeed, this is exactly the approach of the Education for All initiative and a central element of the Millennium Development Goals. But there are also some nagging uncertainties that exist with this strategy. First, developed and developing countries differ in a myriad of ways other than schooling levels. Second, a number of countries – both on their own and with the assistance of others – have expanded schooling opportunities without seeing any dramatic catch-up with developed countries in terms of economic well-being. Third, countries that do not function well in general might not be more able to mount effective education programs than they are to pursue other societal goals. Fourth, even when schooling policy is made a focal point, many of the approaches undertaken do not seem very effective and do not lead to the anticipated student outcomes. In sum, is it obvious that education is the driving force, or merely one of several factors that are correlated with more fundamental development forces? We begin with a review of research on economic growth, an area of considerable interest over the past quarter century. We then demonstrate two things: First, better measurement of human capital that incorporates international test data can dramatically enhance our ability to understand differences in international growth rates across countries; second, consideration of cognitive skills also dramatically lessens concerns about the modeling of cross-country differences in growth.