Are Single-Sex Schools Good for Girls? A Brief Review of Trends and Statistics

In the past, I have had some concerns about the effects of single-sex education, especially after reading an article in the AJC in which parents talk about how great it is that their sons are allowed to shout-out answers in the boys' school while the girls' school students are becoming "young ladies." However, if anything could convince me that single-sex education is actually good for building girls' confidence, it would be this video promoting Girls Prep (via Feministing):

After watching this clip, I had to acknowledge that many elementary schools do not have an abundance of images of successful women or minorities. In a school that consciously focuses on confidence-building for girls, students will be presented with positive role models on a daily basis. This could be a great advantage for girls who would otherwise be in male-centric environments and saddled with the 'boys will be boys' but 'girls will be good' stereotypes.

Yet, while opinions abound about whether single-sex or coed classrooms are most effective, solid research on the matter is practically non-existent. According to Diane S. Pollard of the University of Wisconsin:

At this point few definitive conclusions can be drawn about the overall impact of current efforts to implement single-sex classes, especially with respect to their impact on girls. Three problems associated with much of the research and practice in this area make it difficult to offer a general assessment of single-sex classes: (1) the disparity in the goals of single-sex classes, (2) the differences in how these classes have been implemented, and (3) the lack of systematic, long-term research.

The Department of Education seems to be of the same opinion, stating:

Research in the United States on the question of whether public single-sex education might be beneficial to males, females or a subset of either group (particularly disadvantaged youths) has been limited.

They did, however, attempt to do a systematic review of all the studies on the benefits of single-sex research done to date. As you can see, they ran into a few problems:

Of the 88 quantitative studies, 48 were eliminated after further review using the coding guide, and 40 studies met the inclusion criteria and were retained. The reasons for the exclusion of these articles were 1) failure to operationalize the intervention properly; 2) failure to apply statistical controls during the analyses; 3) work that was actually qualitative in nature rather than quantitative; 4) work performed in a non-Westernized country and therefore not comparable; 5) work written in a foreign language and therefore not codable by the researchers; 6) failure to draw comparisons between SS and CE schools; and 7) participants not of high school, middle, or elementary school age.

Forty studies did meet these criteria and were evaluated by the Department of Education. A summary of the results of these forty can be found on this table, which categorizes each as pro single-sex ed, pro co-ed, null, or mixed. While “roughly a third of all studies reported findings favoring SS schools, with the remainder of the studies split between null and mixed results,” the Department of Education does note that:

There is a dearth of quality studies (i.e., randomized experiments or correlational studies with adequate statistical controls) across all outcomes. Even using the more relaxed criterion of allowing correlational studies, each outcome has only limited candidate studies. Too few researchers report descriptive statistics or effect sizes. Mathematics achievement test scores, English achievement test scores, and school subject preference were the only outcomes to have 10 or more qualifying studies. Even within these three categories, the studies differ in the criteria they use and the statistical controls they use to compare SS and CE schooling. This somewhat limits the arguments that can be built and extended from this quantitative review and renders it nearly impossible to conduct a meta-analysis on any outcome area. Many of the remaining studies have other conceptual or interpretive flaws. Many of the studies lacked well-developed hypotheses, and the hypotheses were often not linked directly to the outcomes being studied.

Of course, there is the National Association for Single Sex Public Education, whose sole mission is to promote research that supports single-sex education. Their website, however, relies mainly on anecdotal evidence to support its thesis that same sex classrooms are preferable and merely summarizes data instead of providing links to any original studies. Worse, I felt that this site was intellectually dishonest in the presentation of the little data that they did summarize. For example, the first study mentioned by the NASSPE involved only the fourth grade students at one Florida school, Woodward Avenue Elementary. Woodward Avenue has six classes of fourth graders, and the average class size is about 14 students per class. That means that only about 84 students participated in the study. Half the fourth graders in the study were enrolled in single-sex classrooms while the others spent the year in co-ed classrooms. According to the NASSPE, the percentages of students “scoring proficient” on the end-of-year Florida Comprehensive Assessment Test were as follows:

boys in coed classes: 37% scored proficient

girls in coed classes: 59% scored proficient

girls in single-sex classes: 75% scored proficient

boys in single-sex classes: 86% scored proficient

While these results are dramatic, they are also problematic since the results for the boys and girls in co-ed classes are dramatically less that the state-wide proficiency levels. In classrooms across the state, 86% of fourth graders scored at or above the proficiency level of 3.5. Since the results for the students in co-ed classrooms at Woodward Avenue are so much lower than the scores of students state-wide (who were also enrolled in co-ed classrooms), they are not a credible standard against which we could measure the scores of the single sex classrooms. The question begged by the numbers published by the NASSPE is not why the single sex class scores were so high (they were actually in keeping with the state averages of students in coed classrooms), but what could have gone so very wrong in the coed classrooms that only 37% of boys passed.

So it seems that, for now, no overall conclusions can be made. Since single-sex schools are most often private, perhaps the most important task for parents deciding whether a single sex school is right for their daughter is evaluating the ideology of any individual school. In the case of Girls Prep, the decision to have single sex classrooms is motivated by the desire to give girls access to the affirmative environment that boys generally have in any classroom. This is not the motivation for all single sex classrooms, and parents will have to continue to evaluate the appropriateness of each school environment for their students.