Nearly two months after a contentious labor battle between Chicago teachers and the city, the Chicago Teachers Union is striking yet another blow in a report that calls the city's school system one of "educational apartheid."

The report, which was prepared by five researchers working for the union, aims to highlight the shortcomings of the city’s efforts to close neighborhood schools and replace them with privately-run charter schools. It contends education reform efforts have fostered racial segregation and hindered academic gains.

“When it comes to matters of race and education in Chicago, the attack on public schools is endemic,” CTU President Karen Lewis said in a release. “Chicago is the most segregated city in the country, and our students of color are routinely deemed as second-class by a system that does nothing but present one failed policy after the next.”

According to the report, 88 percent of students affected by CPS closings since 2001 are African-American, and schools enrolling more than 99 percent students of color have been a primary target of CPS school actions, representing more than 80 percent of all affected schools. The union’s report also takes issue with the teacher-student diversity gap that is especially apparent in charter schools; while more than 95 percent of students at charters are black or Latino, only a combined 30 percent of teachers are.

However, a 2009 report by the RAND Corporation appears to contradict the union’s claims. Among other things, the RAND report examined the racial and ethnic mix of the student bodies at both new charter and old public schools. It found that transfers from neighborhood schools to charter schools in Chicago do not increase racial stratification across the schools; rather, transferred students moved to schools with similar or slightly lower proportions of other students of the same race and ethnicity.

The union especially takes issue with the district's push to shutter public schools in favor of opening more charters. Even if Chicago Public Schools closed 100 schools, the report argues, its annual savings of $50-$80 million would constitute only 1-1.5 percent of the district’s operating budget. The report also notes Chicago has the highest class sizes in Illinois and argues closing public schools will only force more students into overcrowded classrooms.

Chicago Public Schools Chief Executive Barbara Byrd-Bennett disputed those claims. “The fact is that CPS simply has too many underused buildings, and too few students,” she said in a statement. “Much of this is due to Chicago having 112,000 fewer school-aged children than the last decade, resulting in dwindling school populations.”

She went on to say that more than half of the district’s schools are underutilized and nearly 140 are half-empty, diverting resources that could be used elsewhere.

The union claims the district's resources are already going too heavily to charter schools. The report finds charter school spending increased by 624 percent between fiscal years 2004 and 2012, despite the district’s calls for overall spending reductions.

Overall, the union is pushing for CPS to end what it calls a “failed policy” of replacing neighborhood schools with charters, and instead “provide neighborhood schools with the resources needed to give students and parents the schools they deserve.” One of the biggest arguments in favor of charter schools -- that they outperform CPS neighborhood schools -- is also one of the biggest myths, the report attests.

According to the union, among elementary schools where 90 percent of the student population qualifies for a free or reduced lunch, charters average at the 33rd percentile in reading test score gains. Their neighborhood school counterparts, by comparison, score in the 43rd percentile. On average, non-selective magnet schools outrank charters by 12 percentile points in reading and two percentile points in math.

CPS cited its Charter Performance Report, which compares charters to the neighborhood schools students would otherwise attend. According to the 2011 comparison, over 80 percent of charters outperformed neighborhood schools in various categories, including dropout rate, attendance rate and graduation rate. Additionally, more than 80 percent of charters outperformed their neighborhood counterparts on two key state exams.

The RAND Corporation report found evidence that Chicago’s charter high schools may produce better ACT scores and heighten the probability of graduating and the probability of enrolling in college, but those positive outcomes were solidly evident only in the charter high schools that also included middle school grades.

Earlier on HuffPost:

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  • Leslie Sabbs-Kizer, Nkai Melton, Akaira Melton, Khaymya Smith

    Leslie Sabbs-Kizer, right, walks her children Nkai Melton, 8, Akaira Melton, 7, and Khaymya Smith, 3 to Bond Elementary school in Chicago, for the first day of classes Wednesday morning, Sept. 19, 2012, after Chicago teachers voted to suspend their first strike in 25 years. Union delegates voted overwhelmingly Tuesday night to suspend the walkout after discussing a proposed contract settlement with the nation's third largest school district. (AP Photo/M. Spencer Green)

  • Students gather outside Benjamin E. Mays Academy , Wednesday morning, Sept. 19, 2012 in Chicago, after Chicago teachers voted to suspend their first strike in 25 years. Union delegates voted overwhelmingly Tuesday night to suspend the walkout after discussing a proposed contract settlement with the nation's third largest school district. (AP Photo/M. Spencer Green)

  • Two students hug, right, as they gather outside Benjamin E. Mays Academy Wednesday morning, Sept. 19, 2012, after Chicago teachers voted to suspend their first strike in 25 years. Union delegates voted overwhelmingly Tuesday night to suspend the walkout after discussing a proposed contract settlement with the nation's third largest school district. (AP Photo/M. Spencer Green)

  • Students walk through the gates outside Benjamin E. Mays Academy, Wednesday morning, Sept. 19, 2012, after Chicago teachers voted to suspend their first strike in 25 years. Union delegates voted overwhelmingly Tuesday night to suspend the walkout after discussing a proposed contract settlement with the nation's third largest school district. (AP Photo/M. Spencer Green)

  • Students gather outside Benjamin E. Mays Academy Wednesday morning, Sept. 19, 2012, after Chicago teachers voted to suspend their first strike in 25 years. Union delegates voted overwhelmingly Tuesday night to suspend the walkout after discussing a proposed contract settlement with the nation's third largest school district. (AP Photo/M. Spencer Green)

  • Rahm Emanuel, Jean-Claud Brizard, David Vitale

    Chicago Mayor Rahm Emanuel, center, is flanked by Chicago Public Schools CEO Jean-Claud Brizard, left, and school board president David Vitale during a news conference after the teachers union House of Delegates voted to suspend their strike Tuesday, Sept. 18, 2012, in Chicago. The city's teachers agreed to return to the classroom after more than a week on the picket lines, ending a spiteful stalemate with Emanuel that put teacher evaluations and job security at the center of a national debate about the future of public education. (AP Photo/Charles Rex Arbogast)

  • Karen Lewis

    Karen Lewis, president of the Chicago Teachers Union smiles as she talks with reporters after the union's House of Delegates voted to suspend the strike Tuesday, Sept. 18, 2012, in Chicago. (AP Photo/Charles Rex Arbogast)

  • Members of the Chicago Teachers Union's House of Delegates celebrate after the delegates voted to suspend the strike against the school district Tuesday, Sept. 18, 2012, in Chicago. The city's teachers agreed to return to the classroom after more than a week on the picket lines, ending a spiteful stalemate with Mayor Rahm Emanuel that put teacher evaluations and job security at the center of a national debate about the future of public education. (AP Photo/Charles Rex Arbogast)

  • Tennille Evans

    Tennille Evans, a member of the Chicago Teachers Union's House of Delegates, celebrates after the delegates voted to suspend the strike against the school district Tuesday, Sept. 18, 2012, in Chicago. The city's teachers agreed to return to the classroom after more than a week on the picket lines, ending a spiteful stalemate with Mayor Rahm Emanuel that put teacher evaluations and job security at the center of a national debate about the future of public education. (AP Photo/Charles Rex Arbogast)

  • Mary Edmonds

    Mary Edmonds, a member of the Chicago Teachers Union's House of Delegates, celebrates after the delegates voted to suspend the strike against the school district Tuesday, Sept. 18, 2012, in Chicago. The city's teachers agreed to return to the classroom after more than a week on the picket lines, ending a spiteful stalemate with Mayor Rahm Emanuel that put teacher evaluations and job security at the center of a national debate about the future of public education. (AP Photo/Charles Rex Arbogast)

  • Teachers picket outside Morgan Park High School in Chicago, Tuesday, Sept. 18, 2012, as a strike by the Chicago Teachers Union continues into its second week. CTU members in the nation's third-largest city will pore over the details of a contract settlement Tuesday as the clock ticks down to an afternoon meeting in which they are expected to vote on ending a seven-day strike that has kept 350,000 students out of class. (AP Photo/M. Spencer Green)

  • Patty Westcott

    Teacher Patty Westcott pickets outside Clissold Elementary School in Chicago, Tuesday, Sept. 18, 2012, as a strike by the Chicago Teachers Union continues into its second week. CTU members in the nation's third-largest city will pore over the details of a contract settlement Tuesday as the clock ticks down to an afternoon meeting in which they are expected to vote on ending a seven-day strike that has kept 350,000 students out of class. (AP Photo/M. Spencer Green)

  • FILE - In this Sept. 14, 2012, file photo Madison teachers hold a unity rally for striking Chicago teachers at the Wisconsin state Capitol in Madison, Wis. Wisconsin's attorney general planned to ask a judge Tuesday, Sept. 18, 2012, to put on hold his decision issued last week repealing major parts of Gov. Scott Walker's law effectively ending collective bargaining for most state workers. The request comes as school districts and local governments attempt to understand the ramifications of the decision and whether it opens the door to new negotiations previously barred with unions. (AP Photo/Wisconsin State Journal, M.P. King, File)

  • Chicago Teacher's Strike Enters Second Week

    CHICAGO, IL - SEPTEMBER 17: Tyler Whitaker watches from a distance as teachers from the Jose De Diego Community Academy, where he is a third grade student, walk the picket line on September 17, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off of their jobs on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Smaller, more subdued groups of teachers picket outside Morgan Park High School in Chicago, Monday, Sept. 17, 2012, as a strike by Chicago Teachers Union members heads into its second week. Mayor Rahm Emanuel said he will seek a court order to force the city's teachers back into the classroom. (AP Photo/M. Spencer Green)

  • Chicago Teacher's Strike Enters Second Week

    CHICAGO, IL - SEPTEMBER 17: Striking Chicago public school teachers attend a press conference by The Chicago Teachers Solidarity Campaign outside the office of Mayor Rahm Emanuel in City Hall on September 17, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off the job on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Chicago Teacher's Strike Enters Second Week

    CHICAGO, IL - SEPTEMBER 17: Striking Chicago public school teachers attend a press conference by The Chicago Teachers Solidarity Campaign outside the office of Mayor Rahm Emanuel in City Hall on September 17, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off the job on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • A handful of teachers picket outside Shoop Elementary School in Chicago, Monday, Sept. 17, 2012, as a strike by Chicago Teachers Union members heads into its second week. Mayor Rahm Emanuel said he will seek a court order to force the city's teachers back into the classroom. (AP Photo/M. Spencer Green)

  • Chicago Teacher's Strike Enters Second Week

    CHICAGO, IL - SEPTEMBER 17: Striking Chicago public school teachers picket outside of George Westinghouse College Prep high school on September 17, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off of their jobs on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Karen Lewis, Jesse Sharkey

    Chicago Teachers Union President Karen Lewis, left, listens to CTU Vice President Jesse Sharkey speak at a press conference following a meeting of delegates Sunday, Sept. 16, 2012 in Chicago. The Chicago teachers union decided Sunday to continue its weeklong strike, extending an acrimonious standoff with Mayor Rahm Emanuel over teacher evaluations and job security provisions central to the debate over the future of public education across the United States. (AP Photo/Sitthixay Ditthavong)

  • A young boy holds a placard in support of striking Chicago school teachers as they march after a rally Saturday, Sept. 15, 2012 in west Chicago. (AP Photo/Sitthixay Ditthavong)

  • Striking Chicago school teachers march after a rally Saturday, Sept. 15, 2012 in Chicago. Thousands of striking Chicago public school teachers and their allies packed a city park Saturday in a boisterous show of force as union leaders and the district tried to work out the details of an agreement that could end a week-long walkout.(AP Photo/Sitthixay Ditthavong)

  • A young girl plays a toy horn as striking Chicago teachers rally Saturday, Sept. 15, 2012, in Chicago. Union president Karen Lewis reminded that although there is a "framework" for an end to their strike, they still are on strike. (AP Photo/Sitthixay Ditthavong)

  • Karen Lewis

    Karen Lewis, president of the Chicago Teachers Union addresses the crowd during a rally Saturday, Sept. 15, 2012, in Chicago. Lewis reminded that although there is a "framework" for an end to their strike, they are still on strike. (AP Photo/Charles Rex Arbogast)

  • Karen Lewis

    Karen Lewis, president of the Chicago Teachers Union addresses union menbers during a rally Saturday, Sept. 15, 2012, in Chicago. Lewis reminded that although there is a "framework" for an end to their strike, they still are on strike. (AP Photo/Sitthixay Ditthavong)

  • Karen Lewis

    Karen Lewis, president of the Chicago teachers union , left, and vice president Jesse Sharkey stand before a meeting of the union's House of Delegates Friday, Sept. 14, 2012, in Chicago. (AP Photo/Charles Rex Arbogast)

  • Karen Lewis

    Chicago Teachers Union president Karen Lewis arrives for a meeting of the union's delegates Friday, Sept. 14, 2012, in Chicago. The city's nearly weeklong teachers strike appeared headed toward a resolution Friday after negotiators emerged from marathon talks to say they had achieved a "framework" that could end the walkout in time for students to return to class Monday. (AP Photo/Charles Rex Arbogast)

  • David Vitale

    Chicago Board of Education President David Vitale speaks to reporters following negotiations with the Chicago Teachers Union on Friday, Sept. 14, 2012 in Chicago. After a week of public school teachers striking over issues that include pay raises, classroom conditions, job security and teacher evaluations, Vitale said the district and teachers union have agreed on a

  • Public school teachers rally at Chicago's Congress Plaza to protest against billionaire Hyatt Hotel mogul Penny Pritzker, who is also a member of the Chicago Board of Education on Thursday, Sept. 13, 2012. Protesters said that $5.2 million in Tax Increment Financing (TIF) funds being used to build a new Hyatt hotel in Hyde Park would be better spent on meeting basic student needs. (AP Photo/Sitthixay Ditthavong)

  • A large crowd of public school teachers rally at Chicago's Congress Plaza to protest against billionaire Hyatt Hotel mogul Penny Pritzker, who is also a member of the Chicago Board of Education on Thursday, Sept. 13, 2012. Protesters said that $5.2 million in Tax Increment Financing (TIF) funds being used to build a new Hyatt hotel in Hyde Park would be better spent on meeting basic student needs. (AP Photo/Sitthixay Ditthavong)

  • Striking Chicago public school teachers and their supporters march down Michigan Avenue on September 13, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off the job on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Striking Chicago public school teachers and their supporters rally following a march down Michigan Avenue on September 13, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off the job on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Striking Chicago public school teachers and their supporters march down Michigan Avenue on September 13, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off the job on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Teachers picket outside the Chicago Public Schools headquarters on September 13, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off of their jobs on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Striking Chicago public school teachers and their supporters march down Michigan Avenue on September 13, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off the job on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Striking Chicago public school teachers and their supporters rally before a march down Michigan Avenue on September 13, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off the job on September 10 after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • Thousands of public school teachers and their supporters rally outside the Hyatt Regency Hotel to protest against Penny Pritzker, whom they accuse of benefiting from being a board member of both the Chicago Board of Education and Hyatt Hotels on Thursday, Sept. 13, 2012 in Chicago. (AP Photo/Sitthixay Ditthavong)

  • Children in strollers join thousands of public school teachers rallying outside the Hyatt Regency Hotel, protesting against Penny Pritzker, whom they accuse of benefiting from her position on the boards of both the Chicago Board of Education and Hyatt Hotels on Thursday, Sept. 13, 2012 in Chicago. (AP Photo/Sitthixay Ditthavong)

  • Two-year-old identical twins Colton and Lucas Jordan join thousands of public school teachers and their supporters as they march along Chicago's Michigan Avenue, protesting against Penny Pritzker, whom they accuse of benefiting from her position on the boards of both the Chicago Board of Education and Hyatt Hotels on Thursday, Sept. 13, 2012. (AP Photo/Sitthixay Ditthavong)

  • Thousands of public school teachers and their supporters rally outside the Hyatt Regency Hotel to protest against Penny Pritzker, whom they accuse of benefiting from her position on the boards of both the Chicago Board of Education and Hyatt Hotels on Thursday, Sept. 13, 2012 in Chicago. (AP Photo/Sitthixay Ditthavong)

  • Teachers and their supporters rally in downtown Chicago on day four of the strike Thursday, Sept. 13.

  • Teachers and their supporters rally in downtown Chicago on day four of the strike Thursday, Sept. 13.

  • Teachers and their supporters rally in downtown Chicago on day four of the strike Thursday, Sept. 13.

  • Teachers and their supporters rally in downtown Chicago on day four of the strike Thursday, Sept. 13.

  • A large group of public school teachers marches past John Marshall Metropolitan High School on Wednesday, Sept. 12, 2012 in West Chicago. Teachers walked off the job Monday for the first time in 25 years over issues that include pay raises, classroom conditions, job security and teacher evaluations. (AP Photo/Sitthixay Ditthavong)

  • A large group of public school teachers rally at John Marshall Metropolitan High School on Wednesday, Sept. 12, 2012 in West Chicago. Teachers walked off the job Monday for the first time in 25 years over issues that include pay raises, classroom conditions, job security and teacher evaluations. (AP Photo/Sitthixay Ditthavong)

  • A family waves at a large group of public school teachers as they march on streets surrounding John Marshall Metropolitan High School on Wednesday, Sept. 12, 2012 in West Chicago. Teachers walked off the job Monday for the first time in 25 years over issues that include pay raises, classroom conditions, job security and teacher evaluations. (AP Photo/Sitthixay Ditthavong)

  • Chicago public school student Natalia Segal joins the picket line outside of Marshall High School on September 12, 2012 in Chicago, Illinois. More than 26,000 teachers and support staff walked off of their jobs on Monday after the Chicago Teachers Union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. (Photo by Scott Olson/Getty Images)

  • A large group of public school teachers marches past John Marshall Metropolitan High School on Wednesday, Sept. 12, 2012 in West Chicago. Teachers walked off the job Monday for the first time in 25 years over issues that include pay raises, classroom conditions, job security and teacher evaluations. (AP Photo/Sitthixay Ditthavong)

  • A young boy in a cart is pulled along by his mother at the tail of a group of public school teachers marching on streets surrounding John Marshall Metropolitan High School on Wednesday, Sept. 12, 2012 in West Chicago. Teachers walked off the job Monday for the first time in 25 years over issues that include pay raises, classroom conditions, job security and teacher evaluations. (AP Photo/Sitthixay Ditthavong)

  • Thousands of public school teachers rally for the second consecutive day outside the Chicago Board of Education district headquarters on Tuesday, Sept. 11, 2012 in Chicago. Teachers walked off the job Monday for the first time in 25 years over issues that include pay raises, classroom conditions, job security and teacher evaluations. (AP Photo/Sitthixay Ditthavong)