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         The U.S. Department of Education's National Center for Education Statistics recently released a study, "Comparing Private Schools and Public Schools Using Hierarchical Linear Modeling."  Considering math and reading scores for 4th ands 8th grades, the study suggests that the differences between public and private schools for 4th grade reading and 8th grad math "were not significantly different from zero."  This supports those who see no difference in the two educational sectors.   Significant variations were found for 4th grade math, with the public school students scoring  significantly higher than those in private schools, allowing public school partisans to celebrate.  But, wait. Private schools students did significantly better with 8th grade reading, giving private school advocates something to stress.
 
         Since these results allow those with predetermined positions to claim victory, that's what some are doing.  National Education Association President Reg Weaver, surprise, surprise, wrote a commentary (or, perhaps, had it written for him) suggesting the report justifies strong support for public schools and, by implication, all the money lavished upon them.
 
         The irony here is that the major teacher unions have intimated that because the report is favorable for the public schools that President George W. Bush's administration released it very quietly, hoping no one would notice.  This despite the fact that the study has been frequently mentioned in the general press, reported on in depth in the July 18th issue of Education Week, and is posted online for anyone and everyone to see.  Not to mention that it obviously was noted by Weaver and the others who say its release attracted no attention.
 
         Many are issuing their pro or con analyses of the study so that won't be done here, except to note that accepting the conclusion there is no appreciable difference in average student achievement in public and private schools ignores the fact that the former currently cost about $10,000 annually per student while the private schools reportedly spend one-third to one-half that amount, or $3-5,000 per student per year.  Weaver didn't touch upon that fact.
 
         If one source achieves the same results as another, but at half or less of the cost, which is better?
 
         The main purpose here, however, is to encourage those interested in education issues to read the report for themselves, or at least its Executive Summary, something at least some of the protagonists seem not to have done. The full report can be found online at http://nces.ed.gov/nationsreportcard//pubs/studies/2006461.asp
 
         The authors warned against unwarranted conclusions.  Two key paragraphs stressing this warning follow verbatim.  Capitalization is added for major points.  Check for yourself then see who is "spinning."
 
                             "CAUTIONS IN INTERPRETATIONS
 
         When interpreting the results from any of these analyses, it should be borne in mind that private schools constitute a heterogeneous category and may differ from one another as much as they differ from public schools.  Public schools also constitute a heterogeneous category.  Consequently, AN OVERALL COMPARISON OF THE TWO TYPES OF SCHOOLS IS OF MODEST UTILITY.  The more focused comparisons conducted as part of the study may be of greater value. However, INTERPRETATIONS OF THE RESULTS SHOULD TAKE INTO ACCOUNT THE VARIABILITY DUE TO THE RELATIVELY SMALL SIZES OF THE SAMPLE DRAWN FROM EACH CATEGORY OF PRIVATE SCHOOL, AS WELL AS THE POSSIBLE BIAS introduced by the differential participation rates across private school categories.
 
         THERE ARE A NUMBER OF OTHER CAVEATS.   First, the conclusions pertain to national estimates.  Results based on a survey of schools in a particular jurisdiction may differ.  Second, the data are obtained from an observational study rather than a randomized experiment, so the ESTIMATED EFFECTS SHOULD NOT BE INTERPRETED IN TERMS OF CAUSAL RELATIONSHIPS. In particular, private schools are ‘schools of choice.'  Without further information, such as measures of prior achievement, THERE IS NO WAY TO DETERMINE HOW PATTERNS OF SELF-SELECTION MAY HAVE AFFECTED THE ESTIMATES PRESENTED. That is, the estimates of the average difference in school mean scores are confounded with average differences in the student populations, which are not fully captured by the selected student characteristics employed in this analysis."
 
         In brief, while interesting, the study is hardly conclusive and doesn't justify sweeping generalizations.
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         ...according to the latest annual employer survey...84 percent–said K-12 schools are not doing a good job...The top three items cited by employers as evidence of unpreparedness were: . Lack of basic employability skills...(cited by 55 percent); . Deficiencies in math and science ability (51 percent); and deficiencies in reading ability and comprehension (38 percent)."   George A. Clowes, "K-12 Education Reforms Not Working, Manufacturers Say," p. 18, School Reform News, January 2006 (This report is online at http://www.nam.org/2005skillsgap )

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Copyright 2006 David W. Kirkpatrick
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