LMICs, we can draw on the literature to assess the potential of pre-primary to close school readiness gaps. Effect sizes of pre-primary quality on learning in HICs tend to be around 0.1 if not smaller (e.g. Brunsek et al., 2017; Perlman et al., 2016). However, one recent meta-analysis found effect sizes of 0.25 on children’s skills for interventions designed to improve pre-primary quality in HICs and 0.16 for pre-primary quality in LMICs (Holla, Bendini, Dinarte, & Trako, 2021). Quality improvements also had larger impacts than efforts to improve access (Holla, Bendini, Dinarte, & Trako, 2021). Interventions that improve home learning environments tend to have effect sizes in the 0.2-0.3 range if not larger (Dong, Dong, Wu, & Tang, 2020; Knauer, Ozer, Dow, & Fernald, 2019; Zuilkowski, McCoy, Jonason, & Dowd, 2019).

As a point of reference, in Egypt, having a mother with no education versus a university education was associated with a raw readiness gap of 0.86 standard deviations. Trying to close the readiness gap with targeted pre-primary quality interventions alone would require a 5.4 standard deviation increase in pre-primary quality (using an effect size of 0.16 (Holla, Bendini, Dinarte, & Trako, 2021)). Improvements via home learning environments would require 2.9-4.3 standard deviation increases in home environments. These back-of-the-envelope calculations suggest targeted efforts towards **_<u>both</u>_** home environment and pre-primary quality are needed to help close school readiness gaps.

# **_5.4 Areas for future research_**

Our findings point to several important areas for future research and data collection to inform policy. Nationally representative data at the pre-primary stage are rare in LMICs (Raikes, Sayre, & Lima, 2021), and data are important pre-requisite to evidence-based efforts to address inequality. Longitudinal data on young children and the trajectory of their development in LMICs are also much needed to understand critical points for intervention.<sup>22</sup> Further research on promoting pre-primary quality and the impact of quality interventions on ECD is needed. Most of the evidence on what works to promote teaching quality and learning in LMICs comes from the primary level. For instance, only 8% of studies on education in Africa focused on pre-primary (Evans & Mendez Acosta, 2021). Research exploiting the random assignment of kindergarten students in Ecuador demonstrated that teachers’ classroom practices are associated with higher learning (Araujo, Carneiro, Cruz-Aguayo, & Schady, 2016). At the pre-primary level, play-based learning can be particularly important and effective (Attanasio et al., 2019; Wolf, Aber, Behrman, & Tsinigo, 2019). However, play-based approaches can also face backlash from parents or teachers (Wolf, Aber, Behrman, & Tsinigo, 2019).

In addition, further research with rigorous causal identification strategies is needed to assess whether, when, and how pre-primary may help close gaps in ECD, as well as which specific input improvements would be most effective for improving equity and learning. Efforts to examine the impact of quality pre-primary on child development should therefore include estimates of the quality of children’s home learning environments, given the large impact of home environments on children’s learning and potential role of pre-primary and pre-primary quality in closing gaps.

> 22 The Young Lives study is an example of longitudinal data collection that can shed light on important aspects of ECD and interactions with early environments, although the data were not nationally representative (Young Lives, 2017).

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