Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Child Development


There is an ongoing debate regarding the importance of smaller classes in elementary school, and a lack of solid research to support class size policies in preschool. State spending on preschool has nearly doubled in the last five years and currently more than 80 percent of American 4-year olds go to some kind of preschool. Increasing enrollments in preschool coupled with the high costs of reducing the size of classes creates the need to decide how many children should be placed in a preschool classroom.

The majority of states require that programs implement class sizes of 20 and teacher-child ratios of 1:10 (Barnett et al, 2011), but much of the research on class size suggests that class sizes smaller than 20 might be more beneficial for children. This dissertation examines the effects of preschool class size on classroom life and student achievement by drawing upon data from 21 teachers and 354 children that were collected during the 2008-2009 school year. Regular class sizes contained 20 students and reduced class sizes contained 15 students. Either the AM or PM session was randomly assigned to be 15 students for each teacher, so that each teacher taught both a regular and reduced class size.

Children who attended reduced size classrooms were found to partake in more one-to-one interactions with teachers than children in regular size classrooms, but there were no differences between groups in the quality of classroom interactions as measured by the Classroom Assessment Scoring System (CLASS). Children in smaller classrooms also were found to gain more in literacy skills by the end of preschool. In contrast, there were no significant differences between groups in vocabulary or math gains. These results indicate that an assigned difference of five children in a preschool classroom can benefit children's cognitive development after just one school year, but these benefits are not explained by changes in the most commonly used measures of classroom quality, which were minimal. Future endeavors to reduce class size in preschool might be enhanced if coupled with professional development strategies that aim to maximize teachers' effectiveness with smaller classes.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.