New US Studies Show that Public Schools do Better than Private Schools

Critics of public education system have long argued that public schools would benefit from being operated more like private schools. Indeed, this is a central belief of the new Abbott Government and its education minister, Christopher Pyne.

However, there is mounting evidence to the contrary. In addition to recent Australian studies that show declining performance by private schools relative to government schools (here and here ), two new US studies have also undercut the belief that private schools do better than public schools. It appears that making public schools more like private schools is not the answer to improving education.

US policy makers have long relied on market-based models to help improve our schools, believing that private institutions—because they are competitively driven—are better than public ones. A new book, The Public School Advantage, by education academics Christopher and Sarah Theule Lubienski offers powerful evidence showing that public schools in fact outperform private ones.

Drawing on two recent, large-scale, and nationally representative data bases, the authors show that any benefit seen in private school performance now is more than explained by the demographic background of students. Private schools have higher scores because their students largely come from more privileged backgrounds that offer greater educational support.

After controlling for student background factors, the authors show that gains in student achievement at public schools are at least as large, and often larger, than those at private schools. For example, the study found that the raw scores in 4th grade mathematics showed an advantage of 9.6% for Catholic schools over public schools. However, after taking account of location and student background, this positive advantage disappeared and became negative at -7.2%, that is, the advantage was reversed in favour of public schools.

Indeed, demographic differences more than explain any apparent edge in the raw scores of private school students, and by the time they reach middle school, public school students score ahead of their demographically similar, private school peers, with differences ranging from a few weeks to a full grade level, depending on the type of private school.

The study is one of the most comprehensive studies ever done comparing public and private school performance in mathematics, and draws on data on mathematics test results for over 300,000 elementary and middle school students in 15,108 public, charter, and private schools.

The study also shows that the very mechanism that market-based reformers champion – school autonomy – may be the crucial factor that prevents private schools from performing better. In summarising their findings in The Washington Post, the authors stated that autonomy is too often used to maintain outdated strategies that may align with parental preferences but are not particularly effective for educating students.

For example, private school students are more likely than their public school counterparts to sit in rows, complete math worksheets and believe that mathematics is “mostly memorizing facts”. In contrast, public schools have moved beyond traditional, repetitive exercises, and more often ask students to solve complex, real-world problems and to learn geometry, data analysis, and early algebra ideas, in addition to basic arithmetic.

This difference can partly be explained by the fact that public school teachers in the US are more likely to be certified and to receive ongoing training in the field, keeping them current on research-based instructional standards and resources supported by professional entities. Private school teachers are rarely impelled to receive such training. And despite much criticism, teacher certification and up-to-date instructional practices are actually positive correlates of achievement, and the fact that these are more prevalent in public schools helps explain the public school advantage.

The authors say that in competitive conditions schools may try to play to popular demands instead of embracing professional expertise. Parents may not choose schools primarily on the basis of academic effectiveness. School uniforms, the demographics of a school, and sports programs are easier to observe, and parents often consider these, along with religious values, to be more important than the quality of academic instruction. In an environment in which schools are pitted against each other, families may be influenced by marketing images over academic substance, just as fast food marketing successfully focuses on fun and not nutrition.

Another US study to be published in the Journal of Urban Economics next year analyses the causal effects of Catholic primary schooling on student outcomes such as reading and mathematics test scores, grade retention, and behaviour between kindergarten and 8th grade. It finds that while average test scores among Catholic school students are substantially higher than among public school students throughout this grade range, the differences are driven by systematic differences in students’ background across school sector rather than by the greater effectiveness of Catholic schools.

The study adjusted the raw scores for several student characteristics including race, ethnicity, family structure, parental marital status, education, income, employment, and location. As a result, the performance advantage held by Catholic schools on the raw scores diminished substantially to show a negative effect of Catholic school attendance.

The actual Catholic schooling effect was negative in the case of 8th grade mathematics and 5th grade reading and mathematics, and was very slightly positive for 8th grade reading. In the case of 8th grade mathematics the Catholic school advantage of 7.17% on the raw schools diminished to -5.96% after student characteristics were taken into account. For 8th grade reading, the advantage declined from 13.55% to 0.93%; for 5th grade reading it declined from 11.73% to -1.98% and for 5th grade mathematics it declined from 5.98% to -7.53%.

On the basis of these estimates, the study concluded that Catholic primary schooling significantly lowers mathematics achievement in both 5th and 8th grades. Although there is no strong evidence for a negative Catholic primary school effect on reading scores, there is little evidence for a positive effect.

Further additional statistical analysis suggests that the negative impact of Catholic school attendance could be significantly under-estimated because of possible unobservable biases in Catholic school enrolments that could enhance the Catholic school effect. Under certain conditions, Catholic school attendance could have a large negative effect on reading and mathematics in comparison with public schools.

The study also analyses the impact of Catholic schooling on other school outcomes such as attendance, grade repetition and suspension. It finds little evidence of a positive Catholic school effect on these outcomes once student characteristics are taken into account.

The study concludes that Catholic schools do not boost test scores in comparison to public schools. It finds no “discernible beneficial effects of Catholic primary schooling” on reading and mathematics. Indeed, the results point to a substantial negative effect of Catholic schools on mathematics achievement in comparison to public schools.

As with the Lubienski study, it suggests that one possible explanation for the poor performance by Catholic schools compared to public schools is lower teacher quality in Catholic schools. Salaries of Catholic school teachers in the US are significantly lower than for public school teachers. It says it is quite conceivable that Catholic schools face difficulties in attracting high-quality teachers. Another potential explanation for lower Catholic school achievement is superior curriculum design in public schools.

The new US and Australian studies comparing private and public school results should be compulsory reading for Christopher Pyne. One of the Australian studies shows that declining performance by private schools is the main factor behind the fall in Australia’s results in international tests over the past decade. The other studies show that private schools do no better than public schools, and may well do worse. Pyne’s education agenda to make public schools more like private schools promises further declines.

Trevor Cobbold

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