Do increasing participation rates in early childhood education narrow the reading achievement gap between high- and low-SES primary school students?

Background: Many countries around the world are expanding the enrollment of children in early childhood education (ECE) outside the home to improve school readiness and, ultimately, academic achievement. While socioeconomically disadvantaged children are typically underrepresented in ECE, they are often thought to benefit the most from participation. This study empirically tests whether increasing ECE participation rates are associated with reductions in socioeconomic inequalities in ECE participation and, consequently, with decreases in socioeconomic inequalities in reading achievement at the end of primary school. Methods: The study draws on data from 64 education systems participating in PIRLS cycles between 2001 and 2021, comprising 225 country-by-year observations. Using country-fixed effects, we estimate a mediation model to test whether socioeconomic inequalities in ECE participation mediate the relationship between overall ECE participation rates and socioeconomic inequalities in reading achievement. This fixed effects approach controls for time-invariant differences between education systems. We include a set of control variables to account for economic, demographic, and policy-related changes that might confound within-country trends and discuss untestable assumptions that have to be met to interpret the mediation relationship causally. Additionally, we examine international trends in all three variables of interest. Results: As hypothesized, we find that countries with increasing ECE participation rates and decreasing socioeconomic inequalities in ECE participation also show declining socioeconomic inequalities in reading achievement. Internationally, ECE participation rates have risen over time, while both socioeconomic inequalities in participation and socioeconomic inequalities in reading achievement did not show clear trends over time. Conclusions: According to our interpretation, increasing ECE participation rates seem to help reduce socioeconomic inequalities in reading achievement-provided that the increases also reduce disparities in access to ECE. This finding, together with previous research, offers encouraging evidence for countries investing in or planning to expand ECE. Moreover, this study highlights the importance of ensuring that ECE expansion policies specifically address socioeconomic inequalities in participation to mitigate later educational inequalities.