Relative Contributions of Pre-Kindergarten and Kindergarten to Children's Literacy and Mathematics Skills.

A difficulty for developmental researchers is disambiguating children's general maturation from the influence of schooling. In this study, we use a natural experiment to examine the influence of pre-kindergarten and kindergarten schooling experiences on the development of literacy and mathematics. Children (n = 60) whose birthdates fell within two months of the state-determined cut-off date for pre-kindergarten and kindergarten entry were administered four subtests of the Woodcock-Johnson Tests of Achievement III in the fall and spring of the school year. Using hierarchical linear modeling coupled with propensity score matching, children who were starting kindergarten, and who had prior experience in pre-kindergarten, had higher scores on measures of phonological awareness, early reading, and mathematics skills than did children who had not attended pre-kindergarten previously, even though they were essentially the same age. Fall vocabulary scores did not differ in relation to whether children had pre-kindergarten experience. In addition, although children who attended kindergarten as well as those who attended pre-kindergarten exhibited growth on all measures during the school year, children who attended kindergarten demonstrated greater gains in early reading and vocabulary during the school year. These findings highlight the potential of early schooling processes to facilitate children's intellectual growth.