Charter schools are hailed by the U.S. Department of Education, by major foundations, and by corporate and philanthropic organizations as the prime solution to the alleged failures of traditional public schools to educate children, failures underscored by the poor performance of their minority and disadvantaged students.

Four large-scale studies by two respected research institutes, CREDO and Mathematica, comparing charter schools with traditional public schools were reported in 2013. Major newspapers, apparently relying on the press releases, trumpeted that charter schools had shown astonishing results in closing the achievement gap between disadvantaged and not-disadvantaged students.

Achievement tests are the major yardstick used to assess schools. CREDO conducted three national evaluation studies comparing the achievement test performance of students in charter schools with matched students in traditional public schools. Mathematica studied middle schools in the well-regarded KIPP charter school chain. All four studies compared the amount of “gain” or “growth” in achievement test scores over a school year, not the actual levels of achievement. Even with gains, the achievement level may still be well below norms for the test.

Buried deep in its report, one CREDO study states, “Only when the annual learning gain of these student [minority/poverty] subgroups exceeds that of white or non-poverty students can progress on closing the achievement gap be made.” Charter school minority and economically disadvantaged students made some very small gains in reading and math when compared to matched controls in public schools. However, the difference in achievement growth between white non-poverty students in traditional public schools and minority/poverty students in charter schools is the most relevant comparison.

The average gain, in standard deviation units, for minority or poverty students in charter schools when compared to their counterparts in traditional public schools, was about 0.03. However, the average gain for non-minority, non-poverty traditional public school white students was 0.80. The gain was up to 27 times the gain for poverty or minority students in charter schools. The Mathematica study of KIPP middle schools showed similar large gaps in gains.

The CREDO Institute states: “For many charter school supporters, improving education outcomes for historically disadvantaged is the paramount goal.” While all of the groups in both kinds of schools show gains over the years, the achievement gap remains, as it always has when students from homes in poverty are compared to non-poor ones, in this country and internationally. The “paramount goal” to level the field is not being met by charter schools.

Charter school advocates attribute the educational difficulties of disadvantaged students in traditional public schools to ineffective, uncaring teachers, their unions and bureaucratic restrictions. They insist that having a great teacher in every classroom will overcome every limitation. They claim that low expectations for disadvantaged children are the major problem, not the complex negative effects of poverty.

Charter schools are not hindered in their selection of teachers by bureaucratic restrictions, nor are charter school teachers prevented by union restrictions from pursuing the charter school programs. Allegedly, charter schools have great teachers in every classroom. If there are “no excuses” when disadvantaged students do less well than non-disadvantaged students in traditional public schools, the same rules should apply to charter schools.

What excuse do charters have for the persistent achievement test gap between disadvantaged students in charter schools compared to non-disadvantaged students in the public schools? And why continue down a path where the numbers show that the national policy favoring charter schools will make the majority-minority gap worse?

Charter schools are protected by powerful, wealthy individuals and foundations that profess free-market choice and hold anti-union sentiments and pro-privatization beliefs; some advocates are pursuing profit motives. The advocates seem not to be influenced by data despite their insistence they are data-driven.

The reality is that problems associated with a history of discrimination and the complex negative effects of poverty are not easily solved. The solutions require an enormous, long-term societal commitment. The current reforms, however, threaten the very existence of our public schools, which have long been the envy of the entire world.

Adeline Levine, Ph.D., is professor emeritas (sociology) at the University at Buffalo. A former chairwoman of the department, she is the author of “Love Canal: Science, Politics and People,” and other books and articles on educational subjects. Murray Levine, J.D., Ph.D., is distinguished service professor (psychology) emeritus at UB. He has published extensively on educational subjects.