Michele Pellizzari

University of Geneva
Uni Mail, Boulevard du Pont-d’Arve 40,
CH-1211 Geneva 4, Switzerland


NBER Working Papers and Publications

July 2013Understanding Social Interactions: Evidence from the Classroom
with Giacomo De Giorgi: w19202
Little is known about the economic mechanisms leading to the high level of clustering in behavior commonly observed in the data. We present a model where agents can interact according to three distinct mechanisms, and we derive testable implications which allow us to distinguish between the proposed mechanisms. In our application we study students' performance and we find that a mutual insurance mechanism is consistent with the data. Such a result bears important policy implications for all those situations in which social interactions are important, from teamwork to class formation in education and co-authorship in academic research.

Published: Giacomo De Giorgi & Michele Pellizzari, 2014. "Understanding Social Interactions: Evidence from the Classroom," Economic Journal, Royal Economic Society, vol. 124(579), pages 917-953, 09. citation courtesy of

September 2010Class Size and Class Heterogeneity
with Giacomo De Giorgi, William Gui Woolston: w16405
We study how class size and class composition affect the academic and labor market performance of college students, two crucial policy questions given the secular increase in college enrollment. Our identification strategy relies on the random assignment of students to teaching classes. We find that a one standard deviation increase in class-size results in a 0.1 standard deviation deterioration of the average grade. Further, the effect is heterogeneous as it is stronger for males and lower income students. Also, the effects of class composition in terms of gender and ability appear to be inverse U-shaped. Finally, a reduction of 20 students (one standard deviation) in one's class size has a positive effect on monthly wages of about 80 Euros (115 USD) or 6% over the average.

Published: Giacomo De Giorgi & Michele Pellizzari & William Gui Woolston, 2012. "Class Size And Class Heterogeneity," Journal of the European Economic Association, European Economic Association, vol. 10(4), pages 795-830, 08. citation courtesy of

May 2009Be as Careful of the Company You Keep as of the Books You Read: Peer Effects in Education and on the Labor Market
with Giacomo De Giorgi, Silvia Redaelli: w14948
In this paper we investigate whether peers' behavior influences the choice of college major, thus contributing to the mismatch of skills in the labor market. Using a newly constructed dataset, we are able to identify the endogenous effect of peers on such decisions through a novel identification strategy that solves the common econometric problems of studies of social interactions. Results show that, indeed, one is more likely to choose a major when many of her peers make the same choice. We also provide evidence on skills mismatch in terms of entry wages and occupation. We find that peers can divert students from majors in which they have a relative ability advantage, with adverse consequences on academic performance, entry wages and job satisfaction.
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