We adopt a multi-country setup to show that years of schooling have a causal protective effect on the body mass index of females living in nine European countries. No such effect is found for males. The protective effect for European females is not negligible but is smaller than one recently found for the United States and stronger among overweight females. We discuss possible mechanisms justifying both the protective role of education and the gender difference in this role. We argue that the effects of additional schooling on income, the probability of employment, and the frequency of vigorous physical activities, both on and off the job, may help explain our results.

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.

Exploiting admission thresholds to the Bologna day care system, we show using a regression discontinuity (RD) design that one additional day care month at age 0–2 reduces intelligence quotient by 0.5% (4.7% of a standard deviation) at age 8–14 in a relatively affluent population. The magnitude of this negative effect increases with family income. Similar negative impacts are found for personality traits. These findings are consistent with the hypothesis from psychology that children in day care experience fewer one-to-one interactions with adults, with negative effects in families where such interactions are of higher quality. We embed this hypothesis in a model that lends structure to our RD design.