The Pre-K Debates: What the Research Says About Teacher Quality

The body of research on teacher quality is, if nothing else, a mixed bag, in terms of both quality and approach. Studies of the effects of preschool education levels have employed techniques ranging from simple correlations to complex statistical analyses that seek to account for the complexities of interrelated policies and practices that affect teaching and learning. Given just how complex policy and practice are, it may be that the simple correlations are just as informative for policy purposes, but neither approach is particularly satisfactory.  Controlled randomized trials that look at teacher quality might get us farther, but even these may not tell us what we really want to know, and they are few and far between in any case.  Little wonder, then, that some studies find that teachers with higher levels of education have stronger effects on children’s learning while others do not. A 2007 NIEER quantitative summary (meta-analysis) of the literature found a modest positive effect of teachers with a bachelor’s degree compared to those with less education. A few studies in that analysis deserve extra attention because they have obvious strengths:

1. The Cost, Quality and Outcomes Study of child care found that higher levels of teacher education and pay were associated with higher quality as measured by structured observations, and children’s cognitive test scores. A reanalysis that controlled for location and center found no differences between teachers with bachelor’s degrees and those with associate’s degrees or high school diplomas. However, the reanalysis fails to take into account that programs basically hire all their teachers under the same budget constraint, that teachers within a center are not independent performers, and that centers like to assign difficult-to-teach kids to better teachers.

2. The National Institute of Child Health and Human Development (NICHD) study of early care and education has an advantage over most studies because it includes measures of education in the home, thereby more completely modeling the processes that contribute to children’s learning and development. And, it does so over multiple years and not just a few months. Several NICHD studies have found that teacher education contributes to children’s learning and development.

3. Two studies that found no effects of teacher education on children’s learning are a University of Nebraska study of child care centers in four Midwest states and a University of North Carolina study using data from the National Center for Early Development and Learning (NCEDL) Multi-State Study of Pre-K. The latter involved more than 230 classrooms and 800 children. While both have relatively large samples, nether takes into account teacher assignment, apparently assuming that it is random and they do not measure home learning processes. In the Nebraska study, only about seven teachers out of the hundreds interviewed had salaries above $30,000.

To my mind, the most informative evidence comes from real policy changes such as when the New Jersey Supreme Court ordered high-quality preschool provided to all children in 31 low-income school districts. This “natural experiment” was implemented in a public system wherein most children were served by private providers under contract to the districts. Teachers lacking the necessary credentials received scholarships to attend more schooling so they could meet the new standard of a bachelor’s degree and early childhood certification. Salaries were raised to public school levels.  Teachers received coaching on a regular basis. It comes as no surprise to many involved in this dramatic, albeit painful, transition that the quality of teaching as measured by direct observation was transformed, changing from poor-mediocre to good-excellent.

Of course, we can’t pinpoint teacher qualifications as the sole source of success in New Jersey, and I wouldn’t.  Raising qualifications requirements without raising pay from its typically abysmal level is a recipe for disaster.  Honestly, would the field really be debating whether preschool teachers needed to be well-educated if wages were not at issue?  In addition, coaching and a continuous improvement process are certainly important, but it would be equally misguided to conclude that specialized training and professional development alone could produce quality teaching over the long-run with low wages and poorly educated teachers.

Education research rarely provides a basis for certainty and this is particularly true of studies looking at teacher effectiveness where so many variables matter. If policymakers want greater certainty than the existing evidence provides, different sorts of studies will be needed that are based on real policy changes. In the meantime, leading experts in the field provide us with well-reasoned arguments for and sometimes against requiring higher levels of education for preschool teachers than is currently the case in most classrooms across the nation. Their arguments are well represented in The Pre-K Debates, a new book edited by Ed Zigler and Walter Gilliam at Yale and me.  If nothing else, it is always interesting to see university professors argue that their students don’t learn anything useful or that minority students can’t make it in higher education. I’m always happy to put forward Rutgers University as a counterexample.

– Steve Barnett, Director, NIEER

Note: This post is part of a series discussing issues of contention from The Pre-K Debates. For my analysis of universal preschool’s role in economic mobility, see this earlier post in the series.