Is the class schedule the only difference between morning and afternoon shift schools in Mexico?

Double-shift schooling has been implemented in Mexico for several decades as a strategy to achieve universal access to basic education. This study provides evidence on the existence of social inequalities related to the implementation of this schooling model. Using quantitative data from several databases including the National Census, the curriculum-based test ENLACE and the database of the CCT program "Oportunidades", this study shows that, on average, an afternoon shift school has lower quality educational inputs, a higher concentration of poor students, lower academic scores, and higher dropout, over-age, and failure rates than the morning shift school operating in the same building. It also explores how formal and informal institutions may have affected the implementation of the double-shift schooling in Mexico, based on interviews and observations conducted in San Luis Potosí, México.