This paper estimates peer effects originating from the ability composition of tutorial groups for undergraduate students in economics. We manipulated the composition of groups to achieve a wide range of support, and assigned students - conditional on their ability - randomly. The data support a...

In an influential study, Mas and Moretti (2009) find that "worker effort is positively related to the productivity of workers who see him, but not workers who do not see him". They interpret this as evidence that social pressure can reduce free riding. In this paper we report an attempt to...

In an in influential study, Mas and Moretti (2009) found that "worker effort is positively related to the productivity of workers who see him, but not workers who do not see him." They interpret this as evidence that social pressure can reduce free riding. In this paper we report an attempt to...

This paper reports the results of a lab experiment designed to study the role of observability for peer effects in the setting of a simple production task. In our experiment, participants in the role of workers engage in a team real-effort task. We vary whether they can observe, or be observed...