Insights for the OECD's Baby PISA from Mexico's Large-Scale Assessment of Pre-Schoolers

In 2018 the Organisation for Economic Co-operation and Development (OECD) launched its International Early Learning Child Well-being Study (IELS), also known as Baby PISA. In the first round of data collection, the IELS focused on three OECD countries: England, Estonia and the United States. In this article we show that a similar study of pre-schoolers to IELS took place in Mexico -- EXCALE for Pre-school -- and argue there is much the research community can learn from an empirical study of this initiative. Our novel comparative study draws on data from policy documents and interviews with sub-national and municipal education officials in Mexico. We reveal how EXCALE for Pre-school led to a narrowing of teaching practices and standardising student assessment aimed at 5-year-olds. We argue that the Mexican case shows how large-scale assessments bring early years learners into the orbit of official state governing, and that assessment now drives those pedagogical practices that limit the diversity of learning experiences of pre-schoolers.