Religious adherence has been hard to study in part because it is hard to measure. We develop a new measure of religious adherence, which is granular in both time and space, using anonymized mobile phone transaction records. After validating the measure with traditional data, we show how it can...

While observational evidence suggests that people behave more prosocially towards members of their own ethnic group, many laboratory studies fail to find this effect. One possible explanation is that coethnic preference only emerges during times of stress. To test this hypothesis, we...