we should see higher teachers' wages in such villages. Conversely, if the GSS eect works through the supply channel, we should observe lower wages. Therefore, one should test for dierences in skilled women's wages in villages with and without a GSS.<sup>15</sup> However, the challenge in doing so is a data issue: The only available village-level data that captures skilled women's wages is the private school census, which records average teacher wages in all private schools.<sup>16</sup> Since we do not observe wages in villages without private schools, a simple correlation of wages and GSS may be biased, with the bias depending both on how GSS were placed and on the truncation of the wage distribution due to missing wages in villages without private schools. We follow two approaches to address the selection problem. We use a Heckman selection model, where the selection stage is the probability of observing a positive wage, which corresponds to having a private school in the village. Another alternative is to use the control-function approach, where we condition on the predicted probability of observing a non-missing value of the wage-bill in the wage equation (Angrist 1995). Details of both approaches are in Appendix I.

We should caution that we cannot structurally estimate the size of the supply-side eects. For instance, simultaneous changes in the demand for schooling due to GSS construction imply that the supply-side impact of GSS construction on (decreasing) the wage-bill represents a lower bound. Therefore, our strategy indicates the presence of a supply-side impact but has less to say about its size.

> 15If there is a preference to teach in private schools, increased demand could drop wages as teachers may be willing to accept lower wages in new private schools. However, instead there is a strong preference for public schools (better pay and easier job). In addition, the labor market for public and private schools is quite dierent, with the former being non-local and the latter local. Moreover, within private schools, the market is not stratied so it is unlikely that there would be systematic compensating dierentials across dierent private schools. One may also be concerned about whether private school wages are meaningful if the owners also teach (wages may be confounded with prots). We do not think this is a substantive issue. A detailed examination of prots using the smaller sample in the LEAPS database, suggests that median prots are quite comparable to a teacher's wage. Moreover, most of these schools do employ non-family/paid labor and therefore reported wages indeed reect the opportunity cost of hiring (local) skilled women,

> 16An alternate data source is the Pakistan Integrated Household Survey (PIHS). Unfortunately, given the small number of villages that received a GSS, the available sample sizes are too small in the PIHS. With the sample restrictions in our paper, we nd only three villages in the treatment and thirty-one villages in the control set for these data. Moreover, since the majority of (the few) women who work in non-farm activities are teachers, and the vast majority of private school teachers are women, the private school wage bill is likely to reect the wages of skilled women.

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