Public preschool and maternal labor supply

"Beginning in the mid-1960s, many state governments, particularly in the South and West, began to subsidize kindergartens for the first time. These initiatives generated wide variation across states over time in the supply of seats for five year olds in public schools. This paper uses the staggered timing and age-targeting of these preschool expansions to examine how the provision of universal child care through public schools affects maternal labor supply. I find that single women with five year olds but no younger children were more likely to be employed once kindergartens were available. The estimated effect is large, implying that three mothers entered the labor force for every ten children enrolled in public school. By contrast, I detect no significant labor supply response among other single women with eligible children or among married mothers of five year olds. These findings complement other research suggesting that preschools targeted toward at-risk populations, such as children in single-parent families, are more cost effective than universal programs"--National Bureau of Economic Research web site.