Positive effects of single-sex education

Australian research shows that there are “positive effects of single-sex schooling” in relation to numeracy and literacy testing (NAPLAN) and tertiary entrance scores (TES), while a New Zealand study shows that there is a “pervasive tendency for children attending single-sex schools to have greater success”. Studies undertaken in the United States, Trinidad and Tobago, Chile and South Korea also demonstrate the positive impact of single-sex education on academic outcomes.

A 2018 British study found that boys and girls from government single-sex schools are more likely to take academically selective subjects likely to facilitate university entry (including mathematics, physics, chemistry, biology and languages) than their counterparts at government co-educational schools. These results held even when accounting for socioeconomic status (Anders, Henderson, Moulton & Sullivan, 2018, pp. 80, 82, 86, 89).

• A 2017 study of Year 3, 5 and 7 numeracy and literacy (NAPLAN) data by Dr Katherine Dix of the Australian Council for Educational Research (ACER) found that boys and girls at single-sex schools achieved higher scores than co-ed students even when socio-economic status was taken into account. Year 7 boys at single-sex schools were, on average, 1.6 terms ahead of co-ed students in reading and 3.9 terms ahead in mathematics. Year 7 girls at single-sex schools were 4.2 terms ahead of co-ed students in reading and 2.8 terms ahead in mathematics (Dix, 2017, unpaginated).

• A 2017 study led by Christian Dustmann, Professor of Economics at University College London, found that converting educational environments from single-sex to co-ed leads to falling academic results for both boys and girls, but particularly for girls (p. 28). The study — which examined data from South Korea where students were randomly assigned to single-sex and co-ed high schools until 2009 — also showed that “pupils in single-sex schools outperform[ed] their counterparts in coed schools by 5 to 10 per cent of a standard deviation for boys and 4 to 7 per cent for girls” on the College Scholastic Aptitude Test for students taking Korean, English and mathematics from 1996 to 2009 (p. 32). (Also see, Dustmann et al., 2017, Why single-sex schools are more successful.)

• Doo Hwan Kim and Helen Law’s 2012 analysis of Korea’s 2010 College Scholastic Ability Test (CSAT) results also revealed “the advantage of attending a single-sex school”, stating that the “mean scores for both girls’ and boys’ schools were higher than those for their co-ed counterparts in all three major CSAT subjects: Korean, English and maths”.

• Similarly, Hyunjoon Park, Jere Behrman and Jaesung Choi’s 2012 study found that single-sex schools in South Korea are “causally linked with both college entrance exam scores and college-attendance rates for both boys and girls” (p. 23). They concluded that “the positive effects of single-sex schools remain substantial, even after taking into account various school-level variables such as teacher quality, the student-teacher ratio, the proportion of students receiving lunch support, and whether the schools are public or private” (p. 1).

• A 2014 report by Dr Lucy Lu and Karen Rickard for the NSW Centre for Education Statistics and Evaluation, examining numeracy and literacy (NAPLAN) data for junior secondary students and tertiary entrance scores (TES) for senior secondary students, “confirmed the positive effects of single-sex schooling” in the NSW government system, where there are 21 boys’ and 24 girls’ government high schools (p. 33). The report found that after accounting for the variation between schools in intake policies and student characteristics (such as socioeconomic status), “the effect associated with single-sex schooling ranged from 0.08 standard deviations for junior secondary students to 0.2 standard deviations for senior secondary students”. The report notes that this finding “warrants further investigation as to reasons why students appear to achieve more in these schools than in co-educational schools” (pp. 33-34).

• A 2013 report by Dr Sinan Gemici, Patrick Lim and Professor Tom Karmel found that, for “reasons the data cannot uncover, schools which deviate from the norm”, including single-sex schools, “do better” when it comes to tertiary entrance scores and that this is consistent with previous research (p. 19). In fact, two-thirds of all schools they categorised as “high-performing” schools were single-sex (pp. 30-31). Gemici et al. state that “individual factors are the main drivers of success” but school characteristics are responsible for 20% of the variation in tertiary entrance scores and 9% of the variation in university enrolment (p. 36). The three most important school attributes for tertiary entrance scores are school sector, gender mix, and the extent to which a school is academically oriented (p. 8). In other words, “schools matter” when it comes to tertiary entrance scores and the probability of going to university (p. 36). Unlike previous studies, Gemici et al. found that a school’s average socioeconomic status does not influence tertiary entrance scores, but it does affect the probability of a student attending university (p. 8).

• C. Kirabo Jackson (2016) analysed a 2010 experiment by the Ministry of Education in Trinidad and Tobago to convert twenty low-performing, co-educational government secondary schools into single-sex schools. Jackson found that after accounting for student selection, there were “large positive effects” of 0.14 standard deviations for both boys and girls attending the single-sex pilot schools in national exams for academic subjects taken three years after entry (p. 4). In addition, students in the single-sex cohorts were “more likely to earn the secondary school leaving credential”. “Importantly,” he states, “these benefits are achieved at zero financial cost” (p. 1).

• Gandara and Silva (2015, p. 11) examined data for 60,000 high school students in Chile who sat admission tests for entry into science-related degrees in 2010, finding that males outperformed females in the biology, physics and chemistry tests overall, but that male and female students attending single-sex schools outperformed students from co-educational schools in all three tests.

• Cherney and Campbell (2011) found that boys and girls from single-sex high schools in the American Midwest “performed significantly better” on a maths test than their co-educational counterparts, even after controlling for prior grades, age, maths anxiety and domain identification (p. 721).

• A 2002 Australian study reported on a year-long trial of single-sex Year 7 classes at a Queensland primary school, finding that girls in mixed-sex classes reported reduced scores on emotional and behavioural engagement by the end of Year 7, and that boys made significant gains in spelling, reading and mathematics (Gilmore, Patton, McCrindle & Callum, 2002, p. 1).

• A 1999 study by Lianne Woodward, David Fergusson and John Horwood of the Christchurch School of Medicine found that, even after controlling for pre-entry differences in students’ backgrounds, including socioeconomic status, there was a “pervasive tendency for children attending single-sex schools to have a greater success in the School Certificate examinations, higher Burt reading scores, greater school retention, less likelihood of leaving school without qualifications and less exposure to unemployment than children attending coeducational schools”. Woodward et al.’s study was based on data collected from an 18-year longitudinal study of a birth cohort of 668 New Zealand children (p. 2).