""The study from Vanderbilt University's Peabody Research Institute followed more than 1,000 students from pre-K to third grade to assess the impact of Tennessee's preschool program, which serves more than 18,000 low-income students across the state. 

By the end of the preschool program, the researchers found, children enrolled scored significantly higher on math, literacy and language assessments compared with those who were not. At the beginning of kindergarten, teachers also rated the children who were enrolled in the preschool program as being better prepared for kindergarten work, as having better behaviors related to learning in the classroom and as having more positive peer interactions.

However, by the end of kindergarten, the children who were not enrolled in the preschool program had caught up to those who were, and there were no longer differences between them on achievement measures.