*This paper provides new evidence on gender bias in teaching evaluations. We exploit a quasi-experimental dataset of 19,952 student evaluations of university faculty in a context where students are randomly allocated to female or male instructors. Despite the fact that neither students' grades nor self-study hours are affected by the instructor's gender, we find that women receive systematically lower teaching evaluations than their male colleagues. This bias is driven by male students' evaluations, is larger for mathematical courses and particularly pronounced for junior women. The gender bias in teaching evaluations we document may have direct as well as indirect effects on the career progression of women by affecting junior women's confidence and through the reallocation of instructor resources away from research and towards teaching. JEL Classification:J16, J71, I23, J45

This paper estimates peer effects in a university context where students are randomly assigned to sections. While students benefit from better peers on average, low-achieving students are harmed by high-achieving peers. Analyzing students' course evaluations suggests that peer effects are driven by improved group interaction rather than adjustments in teachers' behavior or students' effort. We further show, building on Angrist (2014), that classical measurement error in a setting where group assignment is systematic can lead to substantial overestimation of peer effects. With random assignment, as is the case in our setting, estimates are only attenuated.Keywords: Peer effects, higher education, measurement error, estimation bias JEL classification: I21, I24, J24 * The authors would like to thank two anonymous referees for providing valuable comments and suggestions. We would also like to thank Joshua Angrist, Sandra Black, Lex Borghans, Harold Cuffe, Gigi Foster, Andries de Grip, Monique de Haan, Thomas Dohmen, Andreas Dzemski, David Figlio, Bart Golsteyn, Jonathan Guryan, Daniel Hamermesh, Randi Hjalmarsson, Olivier Marie, Julie Moschion, Derek Stemple, Benedikt Vogt, participants at various seminars and conferences and especially Nicolás Salamanca for helpful discussions and comments. We further thank Joël Castermans, Sanne Klasen and Kim Schippers from the SBE Scheduling Department, Sylvie Kersten from the SBE Exams Office, and Jeannette Hommes and Paul Jacobs from the Educational Research and Development Department for providing data and valuable background information. We thank Sophia Wagner for providing research assistance. -1 - IntroductionThe promise of the peer effects literature is to provide policy makers with advice that can be used to increase overall performance by simply reorganizing peer groups. When looking at the by now substantial number of published articles that estimate peer effects in education, it becomes apparent that the literature has not yet delivered this promise. This can be seen, for example, in the recent review by Sacerdote (2011), who shows that size and even the sign of peer effects estimates notably differ between and even within primary, secondary and post-secondary education.One potential reason why peer effects estimates are so varied is that there are a number of social and statistical forces that lead to similar outcomes between peers, even in the absence of causal peer effects (Angrist, 2014;Manski, 1993). Two well-known challenges to the identification of peer effects are the selection and reflection problem. The selection problem states that peer groups are usually formed endogenously and that it is empirically difficult to distinguish peer effects from selection effects. The reflection problem states that it is impossible to distinguish the effect of peers on the individual from the effect of the individual on peers if both are determined simultaneously. A number of recent peer effects studies (Carrell, Fullerton, & West, 2009;Carrell, Sacerdote, & West, 201...

This paper investigates how high school gender composition affects students' participation in STEM college studies. Using Danish administrative data, we exploit idiosyncratic within-school variation in gender composition. We find that having a larger proportion of female peers reduces women's probability of enrolling in and graduating from STEM programs. Men's STEM participation increases with more female peers present. In the long run, women exposed to more female peers earn less because they (1) are less likely to work in STEM occupations, and (2) have more children. Our findings show that the school peer environment has lasting effects on occupational sorting and the gender wage gap.