This paper uses measurements of learning inequality to explore whether learning interventions that are aimed at improving means also reduce inequality, and if so, under what conditions. There is abundant evidence that learning levels are generally low in low- and middle-income countries (LMIC), but there is less knowledge about how learning achievement is distributed within these contexts, and especially about how these distributions change as mean levels increase. We use child-level data on foundational literacy outcomes to quantitatively explore whether and how learning inequality using metrics borrowed from the economics and inequality literature can help us understand the impact of learning interventions. The paper deepens recent work in several ways. First, it extends the analysis to six LMIC, displaying which measures are computable and coherent across contexts and baseline levels. This extension can add valuable information to program evaluation, without being redundant with other metrics. Second, we show the large extent to which the disaggregation of inequality of foundational skills between- and within-schools and grades varies by context and language. Third, we present initial empirical evidence that, at least in the contexts of analysis of foundational interventions, improving average performance can reduce inequality as well, across all levels of socioeconomic status (SES). The data show that at baseline, the groups with the highest internal inequality tend to be the groups with lowest SES and lowest reading scores, as inequality among the poor themselves is higher than among their wealthier counterparts. Regardless of which SES groups benefit more in terms of a change in mean levels of reading, there is still a considerable reduction in inequality by baseline achievement as means increase. These results have policy implications in terms of targeting of interventions: much can be achieved in terms of simultaneously improving averages and increasing equality. This seems particularly true when the initial learning levels are as low as they currently are the developing world.
