That was the
conclusion of researchers Sarah and Christopher Lubienski in a
last year of data from the 2000 National Assessment of Educational
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.
paper on the study was posted online Jan. 23 by the National
Center for the Study of Privatization in Education, 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
"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 policymaking 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 the
2003 National Assessment of Educational Progress sample of 190,000
fourth-graders in 7,485 schools and 153,000 eighth-graders in 6,092
schools nationally. The schools in the sample were categorized as
non-charter public, charter and private, with the private schools
broken down further by Catholic, Lutheran, conservative Christian
and "other private."
The National Assessment of Educational Progress 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.
The National Assessment of Educational Progress 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 public schools in the
fourth-grade sample when looking just at test scores and about even
with regular publics in the eighth grade.
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However, when the researchers 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
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
To determine differences in students' backgrounds, the
researchers used National Assessment of Educational Progress 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 popular 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 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.
[News release from
University of Illinois at Urbana-Champaign]