The following article originally appeared in The Harvard Education Letter (volume 31, number 1). Copyright 2015 President and Fellows of Harvard College. All rights reserved.

Market forces based on concepts of competition, choice, autonomy, and financial incentives applied to public education will improve learning outcomes. This formula for educational improvement, popularized as long ago as 1990 with the publication of Chubb and Moe’s Politics, Markets and America’s Schools, appears to reflect conventional wisdom today. In fact, these beliefs have gained momentum with the advent of No Child Left Behind, the growth of charter school legislation across the country, and the initiatives reflected in the federal Race to the Top requirements and incentives.
 
Chubb and Moe argued, among other things, that private schools outperform public schools because they (1) compete for students by attracting parents to their services; (2) navigate fewer bureaucratic regulations (e.g., teacher certification requirements); (3) design instructional improvements and reward teachers for good performance, unfettered by union agreements; and (4) respond to the interests of parents and students rather than to self-interested bureaucrats who manage the public schools to perpetuate the strength of their organizations, and to the local politicians who serve on boards of education and represent special community and political interests, rather than the educational interests of parents and students.
 
A new study now calls all of these arguments into question. Conducted by Christopher and Sarah Lubienski, professors at the University of Illinois at Urbana-Champaign, the study is described in their book The Public School Advantage: Why Public Schools Outperform Private Schools. After seeing brief references to it in a couple of articles, I reviewed it as a possible addition to the readings for one of my classes this fall. Called Social and Political Forces in Education Leadership, it is a course in our Education Leadership PhD concentration at George Mason University. Although originally planning to use articles exclusively, I made this book the only required text for the class because it cut across a number of the issues we would be addressing: choice and privatization; charter school growth; teacher recruitment, retention, development, and evaluation; accountability and high stakes testing; and the changing federal role in education. In addition to its relevance, I found it a remarkably well-conducted and well-described study, characterized by its use of two respected national databases and a series of statistical controls designed to identify schools’ actual impacts by accounting for other factors such as student demographics. Additionally, the study is presented in a clear-eyed, nonideological, and objective narrative. Although technically complex, the book reserves most of the technical discussion for its appendices. As a former public school superintendent, I believe it deserves to be read by a large audience of public school practitioners and policy makers, and by members of the public concerned about education.
 
The Lubienskis sought to test market-based arguments, like those of Chubb and Moe, by comparing the outcomes of public and private school students using two national databases. They pointed out that recent studies contained conflicting conclusions regarding the relative effectiveness of public vs. private and traditional public vs. charter schools, primarily because these studies were conducted locally or regionally and are difficult to generalize to the national population—even if the studies attempted to control the impact of the differences in the types of students served (e.g., by race/ethnicity, income, dominant language, location).
 
The Public School Advantage addressed both of these limiting factors by using a methodology intended to control statistically the demographics of the students served and the location of their schools, and using two different nationally representative samples: the 2003 National Assessment of Educational Progress (NAEP) and the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (ECLS-K). The NAEP sample provides a snapshot of student performance for only one year, meaning that it fails to account for any growth in achievement prior to the time of the assessment. The Illinois scholars complemented the analyses of the cross-sectional NAEP with the ECLS-K, which provides the opportunity to analyze growth over a period of years, although it suffers the drawback of loss of students from one year to the next.
 
The Lubienskis limited their analysis of student performance to grades 4 and 8 in mathematics in the NAEP sample and to the growth in mathematics performance from kindergarten to grade 5 in the ECLS-K sample. They focused on mathematics because, compared to reading, it is much more school dependent and less influenced by parents.
 
The NAEP sample included student scores from a sufficient number of schools to permit the analysis of the performance of traditional public schools, charter schools, Lutheran schools, Catholic schools, Conservative Christian Schools, and other private schools. The ECLS-K sample only included enough schools to allow analysis of traditional public schools, Catholic schools, and other private schools. Both assessments provided additional information based on student and teacher information that permitted analysis of possible explanations for the findings.
 
The findings of The Public School Advantage fly in the face of conventional wisdom. Without controlling for either demographics or location, the results remained consistent with conventional wisdom: all sectors of private schools outperformed public schools in NAEP mathematics, while traditional public schools outperformed charter schools at grade 4 but performed less well than charters in grade 8. However, after taking into account the types of students served by sector and the locations of the schools, the conclusions were essentially reversed. Except for Lutheran schools, which scored slightly higher than public schools in grade 4, traditional public schools scored above private schools at both grades and above charter schools in grade 4, while just slightly below charter schools in grade 8.
 
Moving to the analysis of the ECLS-K, the initial achievement of students in kindergarten, after adjusting for demographics, indicated an edge over public schools by other private schools, followed by Catholic schools. However, the fifth grade results, after adjusting for demographics and for initial kindergarten scores, demonstrated a virtual tie between public and other private schools and a slight disadvantage for Catholic schools, signaling greater growth for public school students than for either other private school or Catholic school students.
 
In short, the differences in student performance across school sectors apparently have little to do with market forces such as competition and autonomy and much to do with the demographics of the students served. In fact, after considering demographics, the public schools appear to have a pronounced advantage in student performance.
 
Although not claiming to have found all of the answers to the question of why there is a public school advantage, the authors had enough information regarding the schools, teachers, and students to test a number of possible explanations (e.g., school size, some climate measures, time devoted to math instruction) but arrived at only two factors that predicted differences in achievement across both national samples: the proportion of certified teachers and the proportion of teachers reporting use of “reform oriented” math instruction in public schools. The Lubienskis suggest that the greater autonomy of private schools, rather than increasing effectiveness, may shield them from certification requirements and the need to respond to reform initiatives in instruction that influence public schools.
 
They conclude that although market forces may exert a salutary impact in other realms, “ . . . universal education embodies goals that resist the simplistic imposition of market models for the organization and distribution of schooling for meeting those goals.” It seems to me this is the essential lesson to learn from this important study. The Public School Advantage demonstrates the need for those of us who care about public education to resist reforms driven by ideology, market based or otherwise. Instead, we should insist that the implementation of reform efforts be conditioned on whether they serve the public good and improve student learning.