Our Insights

New Research on Pre-K

Surprising Findings

A variety of state-funded pre-K programs generally produce broad gains in participating children’s learning, as measured at kindergarten entry, according to NIEER’s study published this week in AERA Open.

However, these positive findings come with some important cautions that—in the context of the broader research literature—suggest two key lessons for policy makers.

State-funded pre-K programs in the USA all aim to prepare children for success in kindergarten and beyond by supporting development of the whole child.  Nevertheless, policies that shape the design and implementation of these programs vary dramatically from one state to another. With so much variation, it is questionable whether any common outcomes should be expected.

Prekindergarten Effects on Early Learning at Kindergarten Entry: An Analysis of Eight State Programs found estimated effects on emergent literacy were almost uniformly large — but estimated effects on math were moderate, and estimated effects on language were smallest.

Analyzing a diverse array of public preschool programs from every region of the country, NIEER found they all produced large short-term effects on the simplest, easiest-to-acquire skills. But, on average, programs had much more modest effects on math and, especially, language acquisition. For some states estimated language effects were near zero.

This pattern raises concerns because of the salience of language development in the preschool years, and because large boosts to deep learning in language and math seem more likely to lead to long-term gains in achievement and school success. Research has found language to be particularly predictive of literacy success beyond Grade 3.  Given the field’s concern with the tendency of the effects of large-scale pre-K programs to decline or even disappear as children move through school, this finding is worrying.

Now about those important cautions.  We can’t identify specific state pre-K policies that predict differences among the eight states in the outcomes. In part, this may be because there are so many differences that eight states is too small a sample. In addition, differences in outcomes reflect differences in other ECE arrangements available and not just in state pre-K.  Also, populations and policy contexts differ across states, and those affect outcomes as well.  From this perspective, it is remarkable that we found a robust pattern of effects across these states.

The well-known small-scale programs found to have long-term effects all had a strong focus on language development and deep learning.  David Weikart, a former marine, even called the Perry Preschool approach “verbal bombardment.”  These older programs all produced much larger initial gains in language development than were typical in our study. This suggests that policy makers look at what can be done to increase focus on language development and deep learning in mathematics and other domains wihtout neglecting inter- and intra-personal knowledge and skills.

The other “lesson” suggested by our study is that policy makers cannot be complacent about pre-K program effectiveness.  State preschool program effectiveness cannot simply be assumed, nor can it be adequately measured by simple indicators of basic literacy or numeracy skills.

We recommend states develop more frequent, more rigorous, and broader evaluations of their pre-K programs. Ideally, state pre-K programs would all employ continuous improvement systems that provide information at each level from the classroom to the capitol for planning and improvement of practice and policy.

Critically important to success with continuous improvement are both adequate investments in the workforce and their collective capacity—in classroom teachers and assistants, site-level leaders, and state-level leaders who can advise and support those at the local level.

W. Steven Barnett is a Board of Governors Professor and Senior Co-Director of the National Institute for Early Education Research (NIEER) at Rutgers University. His research includes studies of the economics of early care and education including costs and benefits, the long-term effects of preschool programs on children’s learning and development, and the distribution of educational opportunities. Dr. Barnett earned his Ph.D. in economics at the University of Michigan. 

The Authors

W. Steven (Steve) Barnett is a Board of Governors Professor and the founder and Senior Co-Director of the National Institute for Early Education Research (NIEER) at Rutgers University. Dr. Barnett’s work primarily focuses on public policies regarding early childhood education, child care, and child development.


The National Institute for Early Education Research (NIEER) at the Graduate School of Education, Rutgers University, New Brunswick, NJ, conducts and disseminates independent research and analysis to inform early childhood education policy.