Before revision:  I find that providing access to Head Start can have positive effects on test scores and that these effects can negatively depend on whether access to an alternative preschool was available. In addition , I find that the earning benefits associated with the test score gains can outweigh the net costs for various policies providing access to Head Start .
After revision:  I find that providing access to Head Start can have positive effects on test scores . These effects primarily arise from children who do not have any preschool as an outside option. Performing a cost-benefit analysis , I find that the earning benefits associated with the test score gains can outweigh the net costs for various policies providing access to Head Start .