Preparing Students for Success: How Preschool Expansion May Have Improved Elementary School Outcomes for Children in Baltimore City, Maryland

Introduction:A large body of research illustrates the potential for early childhood interventions to serve as a cost-effective approach to improving outcomes for disadvantaged populations. The recent expansion of publicly available preschool in Baltimore City, Maryland, provides a natural setting through which we can study how preschool programming leads to success in elementary school, putting children on a positive trajectory into early adolescence. 

Methods: This longitudinal analysis follows a cohort of children entering Kindergarten in Baltimore City Public Schools (BCPS) during the 2007-2008 school year through the 3^rdgrade. Using data from BCPS and Head Start records we attributed 92% of the cohort to either BCPS PreK (n=2828), Head Start (n=839), Nonpublic Nursery School (n=670), Daycare (n=323), and home-based care (n=975).  Mixed-effects models stratified by sex were used to calculate the probability of elementary school outcomes by preschool experiences while adjusting for individual- (race, ethnicity, limited English proficiency, free and reduced lunch status) and school-level characteristics (percent minority, percent receiving free and reduced lunch), and school-wide averages for each outcome. In a second series of models, we explored the pathways by which preschool experiences may be associated with standardized testing and grade retention. Through this analysis, we test the hypothesis that variation in elementary school outcomes by preschool programming is at least partially explained (i.e., mediated) by the differences in kindergarten readiness, early identification for special education, and better attendance records.

Results:More than 80% of the Kindergarten cohort remained after four years of follow-up. The BCPS preschool program had most children entering Kindergarten ready to learn (62% males, 76% of females). The largest proportion of students identified for special education was from Head Start (16% males, 8% females). For nearly all standardized tests and chronic absenteeism outcomes, there were no differences between BCPS and Head Start graduates. Children who received home-based care fared the worst across outcomes (e.g., >20% chronically absent, 21% females and 29% males off-grade by year 4). Differences in standardized test scores between children who attended a structured public  program (i.e., BCPS and Head Start) and children who received home-based care were explained by kindergarten readiness, early identification for special education, and better attendance.

Conclusion:  Kindergarten readiness, early identification for special education, and better attendance are three pathways by which public preschool programs may improve standardized test scores in BCPS elementary schools. Results support expansion of public preschool and Head Start in urban areas.