 The empirical turn in economics has also had the effect of increasing the importance of economic history. With some ingenuity, especially in identifying possible instrumental variables, history is full of “natural experiments.” For example (J. Hausman 2016), in 1936, the American Congress voted to pay pensions to veterans of World War I eight years before they were due to be paid. Because the percentages of veterans differed across states, Hausman can use the differing economic performances of states to estimate the effects of the economic stimulus the pensions provided. Although less decisive than randomized controlled trials (which are often impossible to carry out), examination of historical episodes such as this one provide significant evidence concerning economic hypotheses.