and College Attendance: Random Assignment in Seoul High Schools concluded that "Attending all-boys schools or all-girls schools rather than attending coeducational schools is significantly associated with higher average scores." In 2014, E. Pahlke, J. S. Hyde, and C. M. Allison published a meta-analysis in Psychological Bulletin comparing achievement and attitudes in single-sex versus coeducational schools that included 1.6 million students in grades K-12. The study concluded that "there is little evidence of an advantage of SS schooling for girls or boys for any of the outcomes." In a 2015 review of this study, however Cornelius Riordan observed that the authors "employ a 0.2 effect-size threshold in drawing these conclusions about there being no advantage to single-sex schooling. Despite the above conclusion, the research found that, in a separate analysis of just the best studies (well controlled) conducted in America, the effect size in mathematics was 0.14 for both boys and girls. The verbal performance was 0.22 for girls and 0.13 for boys.... Educational research has shown that a standard effect size of 0.10 on gains from sophomore to senior year of high school is equivalent to one full year of learning by the average public school student in the United States." Thus, he says, that "Applying this standard, a difference of 0.10 (or greater) between students in single-sex and in coeducational schools would be substantially important." The analysis of the 21 other countries yielded much smaller effects, such as a 0.10 effect on mathematics for girls and a 0.06 effect for boys and science (0.06 for girls and 0.04 for boys). Most of the international effects, then, would fall within Riordan's stricter criterion for statistical significance. In 2017, Christian Dustmann, Hyejin Ku, Do Won Kwak explained that "While teenage boys may be more likely to be distracted than girls by a mixed-gender school environment (Coleman 1961, Hill 2015), girls may suffer more because of, for instance, an increase in disruptive behaviour (as discussed by Figlio 2007), or a diversion of the teacher’s attention to weaker students (as suggested by Lavy et al. 2012). By region Australia In Australia, most single sex schools are fee paying independent or Catholic schools. There are a small number of single sex government schools, while within the independent sector the proportion of pupils attending single sex schools has dropped from 31% in 1985 to 24% in 1995. Nevertheless, single sex education in Australia is much