We study the effect of providing relative performance feedback information on performance under piece-rate incentives. A natural experiment that took place in a high school offers an unusual opportunity to test this effect in a real-effort setting. For one year only, students received information that allowed them to know whether they were above (below) the class average as well as the distance from this average. We exploit a rich panel data set and find that the provision of this information led to an increase of 5% in students' grades. Moreover, the effect was significant for the whole distribution. However, once the information was removed the effect disappeared. To rule out the concern that the effect may be driven by teachers within the school, we verify our results using national level exams (externally graded) for the same students, and the effect remains.

We discuss the contribution of the experimental literature to the understanding of both traditional and previously unexplored dimensions of gender differences and discuss their bearings on labor market outcomes. Experiments have offered new findings on gender discrimination, and while they have identified a bias against hiring women in some labor market segments, the discrimination detected in field experiments is less pervasive than that implied by the regression approach. Experiments have also offered new insights into gender differences in preferences: to gain less from negotiation, women appear to have lower preferences than men for risk and competition and may be more sensitive to social cues. These gender differences in preferences also have implications in group settings, whereby the gender composition of a group affects team decisions and performance. Most of the evidence on gender traits comes from the lab, and key open questions remain as to the source of gender preferences-nature versus nurture, or their interaction-and their role, if any, in the workplace.JEL classification: J16, J24, J71, C91, C92, C93