Do state preschool programs make a difference for kids? In a word: yes, according to a rigorous assessment from the National Institute for Early Education Research. In a study of 5,071 kindergarten-age children in five states -- Michigan, New Jersey, Oklahoma, South Carolina, and West Virginia -- those who attended state-funded preschool programs scored higher on early language, literacy, and math tests. The differences were statistically significant, and applied to children of all economic backgrounds.