Before revision:  I find that the provision of Head Start access induces parents to enroll their child into Head Start and also positively impacts test scores , and that these effects heterogeneously depend on the availability of access to an alternative preschool  .
After revision:  I find that the provision of Head Start access induces parents to enroll their child into Head Start and also positively impacts test scores , and that these effects can negatively depend on whether access to an alternative preschool .