We study subjects who were asked to fill letters into envelopes with a remuneration independent of output. In the "pair" treatment, two subjects worked at the same time in the same room, and peer effects were possible. In the "single" treatment, subjects worked alone, and peer effects were ruled out. We find evidence of peer effects in the pair treatment because the standard deviations of output are smaller within pairs than between pairs. Moreover, average output is higher in the pair treatment: thus, peer effects raise productivity. Finally, low-productivity workers are the most sensitive to the behavior of peers.

An important component of the long‐run cost of a war is the loss of human capital suffered by school‐age children who receive less education. Austrian and German individuals who were 10 years old during the conflict, or were more directly involved through their parents, received less education than comparable individuals from nonwar countries, such as Switzerland and Sweden. We also show that these individuals experienced a sizable earnings loss some 40 years after the war, which can be attributed to the educational loss caused by the conflict. The implied consequences in terms of gross domestic product loss are calculated.

We investigate the role of gender norms in shaping parental childcare following changes in the relative take-home pay of mothers and fathers. Exploiting variation from Swedish tax reforms, we estimate the elasticity of substitution in parental childcare for native and immigrant couples from a variety of countries characterized by varying gender norms. Couples originating from countries with relatively conservative norms are more likely to reallocate childcare to mothers following a reduction in the father’s tax rate and less likely to reallocate childcare to fathers following a reduction in the mother’s tax rate, thereby reinforcing a traditional allocation of childcare across parents.

We exploit rules of class formation to identify the causal effect of increasing the number of immigrants in a classroom on natives’ test scores, keeping class size and quality of the two types of students constant (pure ethnic composition [PEC] effect). We explain why this is a relevant policy parameter although it has been neglected so far. The PEC effect is sizable and negative (16% of a standard deviation) on language and math scores. For first-generation immigrants, it is more negative (30% of a standard deviation). Estimates that cannot control for endogenous adjustments implemented by principals are instead considerably smaller.

Published online January 27, 2025