Third, we used GPS data to calculate the distance from a child’s house to the nearest preschool built by Save the Children.<sup>34</sup> Figure 2 shows preschool participation by distance to the nearest Save the Children preschool. Enrollment clearly fell with distance and no child travelled more than 5 km to a Save the Children preschool. For the GPS analysis, we ignored the community treatment status and used the distance between a child’s home and the nearest Save the Children preschool as an instrument for preschool participation. Mechanically, this means replacing _T j_ by the continuous distance variable<sup>in equation 3. The estimated treatment coefficient is the</sup><sup>_S_</sup> _ij_ average effect of attending preschool for those affected by the proximity to a Save the Children preschool. These likely included all enrolled children in treatment communities and the set of children in control communities who attended a Save the Children preschool. We estimated program effects using these different constructs of treatment assignment and verified that results were robust to the definition of treatment assignment.<sup>35</sup>

# 6. **Results**

# 6.1. Child Development

We begin by analyzing the aggregate ASQ score, our most comprehensive measure of child development, represented as a z-score transformation of the aggregate score in standard deviations from the mean of the control group. Table 3 presents the results of the ITT and IV regression specifications.<sup>36</sup> Each coefficient is estimated from a separate regression. The intent to treat (ITT) effect in model (1) represents a 0.184 standard deviation (σ) increase in the average total ASQ score from offering the program in treated communities (significant at the 1% level). The IV estimate in model (1), interpreted as the LATE on children enrolled in preschool because of the program’s presence, is an increase of 0.37σ in the total development score. Effects are positive and significant for the sub-domains of communication, problem solving and precise motor coordination, in the range of 0.30σ to 0.35σ in the IV models (columns 2 through 4). The exception

> 34 GPS data was collected at baseline and endline, as well as in a short re-contact survey collected in 2014. Of the 1,897 households with complete surveys, 1,529 households have valid GPS locations.

> 35 See Supplementary Materials Sections 3 and 7. 36 For all tables, we present the control complier mean as a base rate to assess the program impact of the program for the relevant group of children that is affected by the policy. We present an approximation of the implied mean outcome for individuals in the control communities that would have enrolled their child in a preschool if they had the possibility, by assuming the proportion of always takers is low. We calculate the control complier mean by subtracting the estimated effect from the mean of the group of enrolled children in treated communities. For all ASQ domains, our approximation of the control complier means imply that the group of children who would have enrolled in preschool in control communities have lower development scores than other children in their communities.

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