The vast majority of immigrants to the United States at the beginning of the 20th century adopted first names that were common among natives. The rate of adoption of an American name increases with time in the US, although most immigrants adopt an American name within the first year of arrival....

In a randomized control trial, the precision of an average treatment effect estimator can be improved either by collecting data on additional individuals, or by collecting additional covariates that predict the outcome variable. We propose the use of pre-experimental data such as a census, or a...