The "Revista del Centro de Estudios Educativos," numero 3, 1971 included an early Carnoy article on the economics of education: "Un enfoque de sistemas para evaluar la educación, ilustrado con datos de Puerto Rico." The article used a unique data set that had student test scores, students' family background characteristics, and information about teachers and other school inputs for about one-third of all students in Puerto Rican schools to estimate relations between teacher characteristics and student test scores controlling for students' social class, gender, and whether the school was urban or rural. Such data sets were rare in the late 1960s, and so were attempts to understand how education systems worked to produce student learning outcomes--that is, to improve the quality of education. There is a lot to criticize in the empirical analysis in that early article, but it does show that there was considerable concern about the quality of education in Latin America even back in 1971. That concern has grown greatly in the past fifty years as countries in the region have expanded their educational systems to provide an increasing proportion of youth with secondary schooling and higher education. With that expansion, there has been a shift in focus from policies concerned with access to schooling to policies concerned with improving the quality of schooling (UNESCO, 2005).