The efficiency of schools can be measured as the ratio between the outputs produced (achievement) and the inputs utilised (human and technical resources). Once efficiency levels are obtained for each school through Data Envelopment Analysis (DEA) techniques, one can assess how an education system as a whole is either far or close to a maximum efficient educational frontier given available resources. Further, one can rely on this estimated frontier to gauge the importance of students, family and school factors pushing efficiency in different directions, and whether the efficiency-equality trade holds. This exercise is relevant to the realities of education systems of the global south where resources are limited and inequalities are vast. In this paper, we present novel evidence for the Latin America region (9 countries) by using the latest two waves of data from PISA (years: 2018 and 2022), a pooled sample of 4969 schools. Importantly, given the surveys' timing, we are able to compare efficiency before and after the COVID-19 pandemic, contrasting leading determinants. We find that, at regional level, efficiency slightly increased from 0.75 to 0.78, and only being constant in three (Brazil, Chile and Colombia) out of the nine countries. Barriers of efficiency hold across the two waves overall, with systemic factors such as ICT access and school type and location being more empirical relevant post-pandemic. Also, the link between low access to minimum knowledge and efficiency, as well as inclusion, worsened post pandemic in half of the countries. During the pandemic, school efficiency was found to be boosted - among others- by higher school support, better stock of ICT at home and communication with teachers, whereas lack of coordination with education authorities was found to be a barrier.
