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Public schools equal or better in math than private or charter schools
Craig Chamberlain,
Education Editor
217-333-2894; cdchambe@uiuc.edu
1/23/2006
|
CHAMPAIGN, Ill.
— Contrary to common wisdom, public schools score higher in math
than private ones, when differences in student backgrounds are taken
into account.
That was the conclusion of researchers Sarah and Christopher Lubienski
in a study last
year of data from the 2000 National Assessment of Educational Progress
(NAEP).
Now they’re back with similar and more-extensive results in a
follow-up study of the 2003 assessment, drawing from a much larger national
data sample of 13,577 schools and 343,000 students.
The results, the researchers said, raise further questions about the
assumed academic benefits of private, as well as charter, schools. The
results also raise doubts about how effectively parental choice can
influence school quality.
“The presumed panacea of private-style organizational models –
the private-school advantage – is not supported by this (NAEP’s)
comprehensive dataset on mathematics achievement,” the Lubienskis, education professors at the University
of Illinois at Urbana-Champaign, wrote in a summary of their recent
study.
A paper on the study was posted today (Jan. 23) on the Web site of the National
Center for the Study of Privatization in Education (NCSPE), based
at Columbia University. The study was funded through a $100,000 grant
from the Institute of Education Sciences in the U.S. Department of Education.
“More and more states are looking at voucher programs, or trying
to organize public schools on a private-school model, and this study
brings up serious questions about that approach,” Chris Lubienski
said. “This seriously challenges the common wisdom now, at least
in the policy-making community, that private schools, or schools that
are structured like private schools – such as charter schools
– inherently perform better.”
The researchers looked at achievement and survey data from NAEP’s
2003 national sample of 190,000 fourth-graders in 7,485 schools and
153,000 eighth-graders in 6,092 schools. The schools in the sample were
categorized by NAEP as public (non-charter), charter and private, with
the private schools broken down further by Catholic, Lutheran, conservative
Christian and “other private.”
NAEP is considered the only nationally representative ongoing assessment
of U.S. academic achievement, and is often referred to as the “gold
standard” of school performance data.
NAEP tests for more than just math, but the researchers chose to analyze
math achievement because, unlike literacy, it is viewed as being less
dependent on a student’s home environment and more an indication
of a school’s effectiveness, Sarah Lubienski said.
As in the previous study, the researchers found what everyone expects
when looking just at test scores: Private schools did better than regular
(non-charter) publics. “Private schools are always going to do
better if you’re not controlling for demographic differences,”
Sarah Lubienski said.
Charter schools scored lower than regular publics in the fourth-grade
sample, when looking just at test scores, and about even with regular
publics in the eighth grade.
However, when they compared schools with similar student populations,
based on students’ backgrounds – a kind of apples-to-apples
demographic comparison – the private schools’ advantage
disappeared, and even reversed in most cases.
Using a statistical analysis known as hierarchical linear modeling,
the Lubienskis found that regular public schools scored “statistically
significantly higher” than private and charter schools at the
fourth-grade level. With 10 points roughly considered a grade-level
difference in achievement, the regular public schools were trailed by
11.9 points by conservative Christian schools, 7.2 points by Catholic
schools, 4.2 points by Lutheran schools, 5.6 points by all other private
schools, and 4.4 points by charter schools.
At the eighth-grade level, the regular public schools were trailed by
10.6 points by conservative Christian schools and by 3.8 points by Catholic
schools.
Lutheran and charter schools led regular public schools by 1.0 and 2.5
points, respectively, and all other private schools were 2.3 points
below regular public schools – but all of these three gaps were
determined to be statistically insignificant by the researchers.
To determine differences in students’ backgrounds, the researchers
used NAEP survey data related to the students’ socioeconomic status,
which included their eligibility for free or reduced lunch and their
access to learning resources in the home, such as books and a computer.
The researchers also incorporated survey data on students’ race
and ethnicity; gender; disability and limited English proficiency.
The Lubienskis thought the gaps between regular public schools and conservative
Christian schools were especially significant for any discussion about
school choice. “Assumptions that academic quality will be driven
by parental choice need to be re-examined in view of the fact that conservative
Christian schools, the fastest growing segment of the private school
market, were also the lowest performing,” they wrote in their
summary of the research.
The researchers, who are husband and wife, caution that their conclusions
are directed at policymakers rather than parents. They are not telling
parents that the local public school is automatically better, any more
than the common wisdom should tell parents that a local private or charter
school is best. “We could imagine sending our kids to a private
school if the circumstances were right,” Chris Lubienski said.
They also noted that the NAEP samples for some school types were limited,
and cautioned against seeing their research as the last word on the
subject. “We don’t think this is the definitive answer on
this issue, but I do hope that it would put the brakes on – at
least in people’s minds – about this rush to privately run
schools,” Chris Lubienski said.
