The following short summary is an excerpt from the National Association for Single-Sex Public Education
Changing Public Schools to Single Sex Boosts Performance by Both Boys & Girls
Scientific research has long indicated that students in single sex schools do better on standardized tests than those in co-ed situations. However, most experts believed that is because single sex schools tend to be private and expensive. Therefore, students do better because they come from more educated, wealthier families. In addition, private school administrators can expel children who misbehave. They do not have to provide special education programs for children with learning disabilities or problems like Attention Deficit Disorder.
However, a major 2001 study of over 270,000 students by the Australian Council for Educational Research found these assumptions were untrue. Single-sex classrooms and not socio-economic factors boost children's learning. Similar results came from a study of 2954 high schools in England by the National Foundation for Educational Research in 2002.
Several recent experiments also indicate that any school can boost its performance simply by placing boys and girls in separate classrooms.
For example, Thurgood Marshall School in Seattle, Washington, is an elementary school with one of city's highest percentages of low income and minority children. Seven years ago, its principal, Benjamin Wright, converted the school into single sex classrooms, but everything else such as teachers, salary levels, and equipment remained the same. The one simple change produced a dramatic effect. The boys went from the 10th percentile to the 73rd on the Washington Assessment of Student Learning tests. Their reading scores went from the 20th percentile to 66th percentile, and they scored the best in the state in writing. The number of children sent for discipline fell from thirty a day to one or two.
Similar experiments have yielded similar results in the United Kingdom, Canada and the United States.
At an inner city high school in Montreal, student performance jumped from a 66% to an 80% pass rate on final examinations after a switch to single sex education. In Mill Hill County High School, England, test scores rose from 40% to 79% after segregating the sexes.
Researchers at Stetson University performed a three-year pilot study by assigning children to single-sex or co-ed classrooms at Woodward Avenue Elementary School in Deland, Florida. The Woodward students' test scores on the Florida Comprehensive Assessment Tests differed as follows: boys in coed classes: 37% proficient; girls in co-ed classes, 59% proficient; girls in single-sex classes, 75% proficient, and boys in single-sex classes, 86% proficient.
Because these informal experiments produced such dramatic results, professors at Manchester University and Cambridge University in the United Kingdom decided to study the concept of single sex education in a scientific way. The Manchester researchers assigned five public schools to either single sex or coed classrooms. Boys in all-boys schools outperformed boys in the co-ed settings on comprehensive examinations by 68% to 33% pass rates. The girls' scores were 89% versus 48% for the co-ed girls. Similarly, the Cambridge professors studied the effects of single-sex classrooms in rural, suburban and inner city schools. They found that single-sex groupings raised educational achievement in a significant way. For example, after boys were taught French and German separately from girls, 100% passed their examinations. Before the experiment, the pass rate was only 33%.
The conclusion of the "before and after" studies is that single sex education benefits both boys and girls.