Private Vs. Public Schools: Some Surprises
When adjustments are made for differences in family income, public schools compare more favorably with private schools than many would think, writes The New York Times:
A large-scale government-financed study has concluded that when it comes to math, students in regular public schools do as well as or significantly better than comparable students in private schools.It would be interesting to see a thorough analysis of the methodology used in this study. My guess is that much will be made of these findings, but will they stand up to scrutiny?
The study, by Christopher Lubianski [sic] and Sarah Theule Lubianski, [sic] of the University of Illinois at Champaign-Urbana, compared fourth- and eighth-grade math scores of more than 340,000 students in 13,000 regular public, charter and private schools on the 2003 National Assessment of Educational Progress. The 2003 test was given to 10 times more students than any previous test, giving researchers a trove of new data.
Though private school students have long scored higher on the national assessment, commonly referred to as "the nation's report card," the new study used advanced statistical techniques to adjust for the effects of income, school and home circumstances. The researchers said they compared math scores, not reading ones, because math was considered a clearer measure of a school's overall effectiveness.
The study found that while the raw scores of fourth graders in Roman Catholic schools, for example, were 14.3 points higher than those in public schools, when adjustments were made for student backgrounds, those in Catholic schools scored 3.4 points lower than those in public schools. A spokeswoman for the National Catholic Education Association did not respond to requests for comment.
The exam is scored on a 0-to-500-point scale, with 235 being the average score at fourth grade, and 278 being the average score at eighth grade. A 10-to-11-point difference in test scores is roughly equivalent to one grade level.
The study also found that charter schools, privately operated and publicly financed, did significantly worse than public schools in the fourth grade, once student populations were taken into account. In the eighth grade, it found, students in charters did slightly better than those in public schools, though the sample size was small and the difference was not statistically significant.
"Over all," it said, "demographic differences between students in public and private schools more than account for the relatively high raw scores of private schools. Indeed, after controlling for these differences, the presumably advantageous private school effect disappears, and even reverses in most cases."
The findings are likely to bolster critics of policies supporting charter schools and vouchers as the solution for failing public schools. Under President Bush's signature No Child Left Behind law, children in poorly performing schools can switch schools if space is available, and in Washington, D.C., they may receive federally financed vouchers to attend private schools.
Howard Nelson, a lead researcher at the American Federation of Teachers, said the new study was based on the most current national data available. The federation, an opponent of vouchers that has criticized the charter movement, studied some of the same data in 2004 and reported that charter schools lagged behind traditional public ones.
"Right now, the studies seem to show that charter schools do no better, and private schools do worse," Mr. Nelson said. "If private schools are going to get funding, they need to be held accountable for the results."
Supporters of vouchers and charter schools, however, pointed to the study's limitations, saying it gave only a snapshot of performance, not a sense of how students progressed over time. Jeanne Allen, president of the Center for Education Reform, said other state and local studies showed results more favorable to charter schools.
Nelson Smith, president of the National Alliance for Public Charter Schools, said that many students went to charter schools after doing poorly in traditional public schools, and took time to show improvement.
"Snapshots are always going to be affected by that lag," Mr. Smith said.
Officials at the federal Education Department, which has been a forceful proponent of vouchers and charter schools, said they did not see this study as decisive. "We've seen reports on both sides of this issue," said Holly Kuzmich, deputy assistant secretary for policy. "It just adds one more to the list."
The study was financed with a grant from the Institute of Education Sciences at the Education Department, but was independent. The federal government is expected to issue two more studies looking at the same data and using similar techniques. Those studies are still undergoing peer review, but are expected to be released in early spring.
The current study found that self-described conservative Christian schools, the fastest-growing sector of private schools, fared poorest, with their students falling as much as one year behind their counterparts in public schools, once socioeconomic factors like income, ethnicity and access to books and computers at home were considered.
Taylor Smith Jr., vice president for executive support at the Association of Christian Schools, which represents 5,400 predominantly conservative Christian schools in the United States, said that many of the group's members did not participate in the national assessment, which he thought could make it a skewed sample. Mr. Smith said he did not know how many schools from other Christian organizations participated.
The report found that among the private schools, Lutheran schools did better than other private schools. Nevertheless, at the fourth-grade level, a 10.7 point lead in math scores evaporated into a 4.2 point lag behind public schools. At the eighth-grade level, a 21 point lead, roughly the equivalent of two grade levels, disappeared after adjusting for differences in student backgrounds.