How does gender composition affect school performance?
Do girls learn more together with girls instead of boys? And what about boys? Possible gender peer effects in learning have been debated since the introduction of mixed-gender education and would have to be taken into account in the design of school systems as well as in the policy response to the recent revival of single-sex schools.
We study this question in the recent paper “Gender Peer Effects in School,a Birth Cohort Approach” (Ciccone i García-Fontes, 2014). Our main result shows a positive and statistically significant gender peer effect of the proportion of girls on the academic results of boys, and positive but not significant on girls.
Early empirical work looked for gender peer effects across schools but could not deal with the selection of students with different skills into different schools. The best evidence that gender composition affects learning in school comes from Hoxby (2000) and Lavy i Schlosser (2011) studies for Texas and Israel respectively. These studies bypass the selection of students with different skills into different schools
by examining the response of academic achievement to within-school differences in gender composition at a given grade level in different years.
Coeducation and gender peer effects related to the gender distribution in the classroom has also been debated recently in Spain, but there is no empirical analysis dut the lack of data. This has chenged recently with the availabity of a detailed dataset from standardized tests administered at all primary schools from the community of Madrid. We have used the sample corresponding to the tests administered during 2009, 2010 and 2001 to estimate gender peer effects for Spain. We find a statistically significant, positive gender peer effect of girls on the academic achievement of boys. A 10-percentage-point increase in the share of girls in a birth cohort improves boys’ overall academic achievement and their achievement in mathematics by around 2.2 percent of a standard deviation. This effect represents about one fifth of the difference between average test scores of students with high school educated parents compared to college educated parents. On the other hand, the effect of the share of girls in a birth cohort on the achievement of girls is statistically insignificant. The effect that we obtain is consistent with the empirical evidence that show that a higher proportion of girls in the classroom implies a better atmosphere that benefits mostly the boys, see for instance Lavy and Schlosser (2011) per a l'evidència empírica. Looking at the global average effect, our results imply that average academic results are maximized when the proportion of boys and girls is the same in the classroom.
In “Gender Peer Effects in School,a Birth Cohort Approach” (Ciccone i García-Fontes, 2014) we develop a theoretical model of a school system with grade retention that we can solve analytically. In our model, students with academic skills below a threshold are retained in a grade at some point during primary school. As a result, academically weak students end up in a lower grade than their academically stronger peers in the same birth cohort. Another important feature of the model is that the gender composition of birth cohorts and the skills of girls and boys in a birth cohort may be subject to exogenous shocks. The question we ask is if and why spurious gender peer effects in academic achievement may emerge when gender peer effects within schools are estimated at the grade level. A main result of our theoretical model is that the grade level approach generally yields spurious gender peer effects in academic achievement even if grade level differences in gender composition were solely driven by exogenous shocks to gender composition at the birth cohort level. Exogenous shocks to the skills of girls and boys at the birth cohort level also translate into spurious gender peer effects at the grade level. The direction of the spurious gender peer effects depends on the impact of grade repetition on students’ academic skills. If grade repetition improves retained students’ academic skills, exogenous shocks to the skills of girls and boys at the birth cohort level lead to a spurious positive gender peer effect of girls on girls’ academic achievement and a spurious negative gender peer effect of girls on boys’ achievement. If students who have been retained in the past perform on average worse academically than non-retained students in the same grade, exogenous shocks to the gender composition of birth cohorts also lead to a spurious positive gender peer effect of girls on girls’ academic achievement and a spurious negative gender peer effect of girls on boys’ achievement.
Other initial random fluctuations, such as fluctuations on student abilities or on the criteria for student retention due to low performance, can also lead to estimations implying wrong conclusions when there is a positive retention rate and when the grade level estimation is used. The estimation approach that we propose, based on birth cohorts, does not have this problem, if the proportion of girls at the different birth cohorts is due to the natural exogenous variation in births in the catchment area of the school.
Taking into account admission rules into primary schools and mobility for the schools of the community of Madrid this seems a reasonable assumption. We also have in the data several variables describing individual and parental carachteristics of the students, which allow us to verify that the proportion of girls within the birth cohorts is not correlated signficantly with these variables.
Ciccone, A & W. García-Fontes (2014). “Gender Peer Effects in School, a Birth Cohort Approach”. Working Paper, Universitat Pompeu Fabra.
Hoxby, C. (2000). “Peer Effects in the Classroom: Learning from Gender and Race” Variation. Working paper 7867, National Bureau of Economic Research.
Lavy, V. & Schlosser, A. (2011). “Mechanisms and Impacts of Gender Peer Effects at School”. American Economic Journal: Applied Economics, 3(2), páginas 1–33.
Antonio Ciccone (Mannheim University, ICREA, Universitat Pompeu Fabra and Barcelona GSE)
Walter García-Fontes (Universitat Pompeu Fabra and Barcelona GSE)