Why Public Schools Outperform Private Schools

The following is an excerpt from the preface and from chapter seven of the book, “Reconsidering Choice, Competition, and Autonomy as the Remedy in American Education.”

There has long been a perception that public schools are second-rate—that anyone who can get their child into a private school should do so. Such desires for private education are so strong that in some districts we’ve even allocated public funds—through voucher and charter programs—to allow those who can’t afford private education a chance to. But what if our underlying assumption is wrong? What if private schools aren’t better? That is the stunning conclusion of The Public School Advantage. Eschewing most ideologies in favor of empirical data, it argues, via evidence, that our longstanding but much-beleaguered public education system is still the best choice we have.

Of the many competing plans to improve America’s schools, one overall agenda distinguishes itself in terms of its logical potential for fundamentally changing education. The innovative strategy of giving parents more choice of schools, of encouraging competition between those schools, and of granting schools more autonomy to satisfy parents—in short, “incentivizing” education—has taken hold as perhaps the most prominent and promising idea for improving American education at its core. This approach is evident in efforts such as charter schools, vouchers and tax credits for private schools, private management of schools, and privatization. All such “incentivist” approaches draw on market mechanisms modeled after the private sector, including the private education sector.

The reason reformers look to the private sector is obvious. The beauty of the logic is its simplicity. Governments and the bureaucracies they generate are thought to lead to overspending and ineffectiveness—whether the U.S. Postal Service, military procurements, or public schools. This is because governments typically administer enterprises on a monopoly basis, setting up barriers to potential competitors in order to protect their own entities in areas such as education. Hence, virtually all public funding goes only to “public” schools that are traditionally regulated by government bureaucrats, run by administrators who have obtained an official endorsement from the state, and staffed by teachers who have been certified by state-approved teacher training programs. As with all monopolies, this may lead to complacency, and even disincentives for employees to innovate or otherwise respond to the needs of their “customers.” But the private sector, driven by choice and competitive market incentives, is thought to produce better outcomes, such as those associated with FedEx, eBay, or private schools. There, school employees have built-in incentives to work harder, or at least more effectively, at providing a better education, for fear of losing students, losing tuition funds, losing their jobs, or even seeing their school “go out of business.”

At least that is what we thought. Indeed, that is the narrative of the market and, increasingly, public policy in the United States and around the globe. Yet the evidence we have found tells quite a different story than what theorists and the current crop of self-proclaimed reformers assert. Specifically, it points to a new, emerging view of the academic performance and impact of public schools in contrast to the outcomes of their more autonomous counterparts in the charter and private sectors. And the question of the impact of different types of schools, or schools in different sectors, is paramount in this era of choice, charter schools, and vouchers for private schools.

Yet, despite the significance and timeliness of this issue, this topic was not really on the research agenda for either of us. We were each happily ensconced in our own work—one studying mathematics instruction and achievement, the other examining school organization and innovations. While the question of achievement in different types of schools had occasionally appeared on the radar of the wider research community in recent years, it was usually around the hotly contested voucher debates—often vicious arguments that seemed to be geared more toward personal acrimony than enlightenment when it comes to social policy. Indeed, like many researchers, we believed the question of a beneficial private school effect on achievement had been essentially settled by the seminal studies of the 1980s and ’90s, and we had virtually no inclination to delve into that area. And then, while examining data on mathematics instruction from the 2000 National Assessment of Educational Progress (NAEP), Sarah added “private school” as a control variable, and some surprising results appeared.

We were both skeptical when we first saw the initial results: public schools appeared to be attaining higher levels of mathematics performance than demographically comparable private and charter schools—and math is thought to be a better indicator of what is taught by schools than, say, reading, which is often more influenced directly and indirectly by experiences in the home. These patterns flew in the face of both the common wisdom and the research consensus on the effectiveness of public and private schools. Immediately, we checked to see what had happened in the analysis, whether “public” and “private” had been “reverse-coded” or some other such error was involved. But after further investigation and more targeted analyses, the results held up. And they held up (or were “robust” in the technical jargon) even when we used different models and variables in the analyses. We eventually posted a technical paper on a respected website and published a short article, which received some attention. And then, like any good researchers, we applied for funding to study this issue in more depth using the most recent, comprehensive databases. The results across datasets are consistent and robust—indicating that these patterns are substantial and stable, regardless of changes in the details of the analyses.

These results indicate that, despite reformers’ adulation of the autonomy enjoyed by private and charter schools, this factor may in fact be the reason these schools are underperforming. That is, contrary to the dominant thinking on this issue, the data show that the more regulated public school sector embraces more innovative and effective professional practices, while independent schools often use their greater autonomy to avoid such reforms, leading to curricular stagnation.

There is an old joke about an economist walking across a college campus with a student. When the student notices a five-dollar bill on the ground, the economist is dismissive: “It can’t be a five dollar bill. If it were, someone would have picked it up.”

While not exactly a rib splitter, this joke illustrates the inherent, if underappreciated, limitations of assumption-driven disciplines such as economics in understanding the world. Too often, people not only interpret evidence through ideological assumptions, but ignore facts that fall outside of, or run counter to, those assumptions. Particularly in areas such as a market theory of education, surrogate evidence on the quality of organizational options based on presumptions of how rationally self-interested individuals would act is often privileged over actual evidence of how organizations are really performing. That is, ideological assumptions often trump empirical evidence.

Such is the case with education. If families—and especially parents with defined preferences for better schooling—are avoiding public schools and are instead competing to get their children into private and charter schools, often paying substantial amounts of their family income toward tuition or other costs, then this must indicate that such independent schools are better, according to this narrow economic logic. Indeed, such a conclusion is constantly affirmed in the media and in reports from countless think tanks and blogs. Yet as the data indicate, those behaviors are not an accurate reflection of the reality of school effectiveness. So why would people pay for a product or service when a superior product or service is available for free? Such was the perplexity expressed by one prominent economist when faced with unexpected patterns such as these:

This result is quite surprising, because it appears to violate simple price theory. Public schools are free; [independent] schools often charge substantial tuition, making them noticeably more expensive than the alternatives. Yet some percentage of parents systematically chooses [independent] schools despite high cost and mediocre performance. Is this real?1
According to this logic, public schools are known to be inferior because people are willing to pay for an alternative; if they had real value, we could tell because people would embrace them … just like they would have embraced the wayward greenback.

Yet the evidence presented here on mathematics achievement — the subject that best reflects school effects — in nationally representative samples of elementary schools suggests otherwise. Despite what many reformers, policy makers, media elites, and even parents may believe, these public schools are, on average, actually providing a more effective educational service relative to schools in the independent sector. In fact, the limitations of our data, if anything, likely underemphasize the notable performance of public schools, given that factors not measured in our data sets would favor private, independent schools—public schools are doing something right that overcomes these factors. While this challenges the very basis of the current movement to remake public education based on choice, competition, and autonomy, our analyses indicate that public schools are enjoying an advantage in academic effectiveness because they are aligned with a more professional model of teaching and learning. Meanwhile, attributes such as operational autonomy championed by the market theory of education—or, as it is increasingly a belief system rather than a policy theory, we might use the term “marketism”—may actually be hindering or even diverting schools in the independent sector from higher achievement as they use their freedom in embracing stagnant, less effective curricular practices.