Studies of single-sex classes in a coeducational school were excluded from review
The list of outcomes of interest needs to be expanded in future research and defined more clearly. For example, outcomes such as teenage pregnancy and bullying in school did not appear in a single study of sufficient quality to be reviewed. Other outcomes that are implicit in arguments for and against SS schooling need to be addressed explicitly. For example, a number of authors have proposed that SS schools are particularly effective for students of lower socioeconomic status and perhaps specifically for those who are members of minority or disadvantaged communities. Unfortunately, only three studies addressed this moderator.
This review should not be interpreted as a condemnation of the work of the dedicated researchers who have chosen to study SS-CE differences, as they may not have been in a position to conduct a randomized experiment on this topic. Such a study has yet to be conducted. However, it could be argued that instead of trying to conduct only all-or-nothing studies of whether SS schooling is better or worse than CE schooling, more careful specification of hypotheses and direct linkage of hypotheses to specific outcomes may show ways to also conduct smaller studies that prove whether certain aspects of SS or CE schooling are beneficial.
Finally, there are limits to what a systematic review can accomplish when an intervention is being judged by multiple criteria and all stakeholders do not share the hierarchy of these criteria. Some issues cannot be resolved by any type of research, even randomized experiments, because they involve issues of philosophy and worldview and represent the relative priorities of dueling stakeholders. There is no way to resolve whether an outcome that is important to one stakeholder group, such as parents, students, civil libertarians, and feminists on both sides of the issue, should be accorded more weight than an outcome valued by another group. What is possible is to separate out fact in the form of evidence from fiction by converting as many claims as possible to testable hypotheses and performing the necessary research. In this way, the two parallel debates can be separated from each other. “Does SS schooling benefit or harm the students, and in what ways?” can be separated from “Is it worth it for society regardless of the benefits or costs?” with each debated on its own merits.
These general implications of the review provide a stepping-stone for future research through the continuation of quality research on extant outcomes, the refinement of methodology, better statistical reporting, and the expansion of the theoretical domain. If heeded, these implications can improve the generalizations made about single-sex schooling and coeducation.
Intervention-The single-sex school had to be one in which students were either completely segregated by sex or were completely segregated for all classes, even if co-located in the same building (i.e., dual academies). This initial screening yielded 379 publications that fit the initial inclusion criteria.
A table summarizing the findings is below. In each row, one of the 32 outcome categories is listed, as well as the total number of studies related to that outcome category and the raw number and percent of findings that either support SS schooling, support CE schooling, are null, or mixed (supporting both CE and SS schooling). While eight of the outcome categories have four or more studies, others have as few as one or two studies. For any outcome category, the percentage of studies falling in any of the dispositions (supporting SS, supporting CE, null, or mixed) and the confidence with which one can use the findings will increase with the number of studies. Therefore, the percentages in the summary table should be treated with caution when only one or two studies appear for that outcome category.
These include work-related long-term outcomes such as job performance, leadership performance, mixed-sex work team performance, performance and leadership in volunteer associations, job involvement, and organizational commitment
Findings regarding school track and subject preferences were mixed, with the overall weight of the findings lying somewhere between pro-SS findings and no differences. A majority of studies favored SS schools on the outcome of higher educational aspirations, as evidenced by SS students showing more interest in and taking more difficult courses. SS schools fostered higher educational and career aspirations for girls. More studies emphasized the positive effect of SS schools on career aspirations than CE schools for boys, but evidence regarding their educational aspirations was mixed. A category called “attitudes toward school” showing mixed results was actually a combination of single studies using somewhat different outcome variables, thus reducing the meaningfulness of the category. In terms of actual behaviors, a few studies focused on delinquency, reporting differences in favor of SS schools that were moderated by individual developmental differences. What is lacking is a conceptual framework to tie together the myriad academic-attitude outcome measures used in this realm so that studies will be more directly comparable.
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 adulthub 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.