Sex Roles

, Volume 69, Issue 7–8, pp 404–422 | Cite as

Effects of Single-Sex Schooling in the Final Years of High School: A Comparison of Analysis of Covariance and Propensity Score Matching

  • Benjamin Nagengast
  • Herbert W. Marsh
  • Kit-Tai Hau
Original Article


Typically, the effects of single-sex schooling are small at best, and tend to be statistically non-significant once pre-existing differences are taken into account. However, researchers often have had to rely on observational studies based on small non-representative samples and have not used more advanced propensity score methods to control the potentially confounding effects of covariates. Here, we apply optimal full matching to the large historical longitudinal dataset best suited to evaluating this issue in US high schools: the nationally representative High School and Beyond study. We compare the effects of single-sex education in the final 2 years of high school on Grade 12 and post-secondary outcomes using the subsample of students attending Catholic schools (N = 2379 students, 29 girls’ schools, 22 boys’ schools, 33 coeducational schools) focusing on achievement-related, motivational and social outcomes. We contrast conventional Analysis of Covariance (ANCOVA) with optimal full matching based on the propensity score that provides a principled way of controlling for selection bias. Results from the two approaches converged: When background and Year 10 covariates were controlled, uncorrected apparent differences between the school types disappeared and the pattern of effects was very similar across the two methods. Overall, there was little evidence for positive effects of single-sex schooling for a broad set of outcomes in the final 2 years of high school and 2 years after graduation. We conclude with a discussion of the advantages of propensity score methods compared to ANCOVA.


Single-sex schooling Propensity score Causal inference High School and Beyond study 


Author note

This research was supported in part by grants to the second author from the UK Economic and Social Research Council and the King Saud University in Saudi Arabia. Requests for further information about this investigation should be sent to Benjamin Nagengast, Department of Education, Center for Educational Science and Psychology, University of Tübingen, Europastr. 6, 72072 Tübingen, Germany; E-mail:

Supplementary material

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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Benjamin Nagengast
    • 1
  • Herbert W. Marsh
    • 2
    • 3
    • 4
  • Kit-Tai Hau
    • 5
  1. 1.University of TübingenTübingenGermany
  2. 2.University of OxfordOxfordUK
  3. 3.University of Western SydneySydneyAustralia
  4. 4.King Saud UniversityRiyadhSaudi Arabia
  5. 5.The Chinese University of Hong KongHong KongHong Kong

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