How to Study the Effects of Service in the Armed Forces

In the field of economics, researchers often adopt randomized, controlled trials in an attempt to remove bias and inconsistency. But sometimes nature can throw up situations that mimic these controlled experiments. Consider a young researcher who was trying to study how veteran status affected an individual's future earnings. What we need here is a source of randomization, or a natural experiment that can mimic control settings. Such an eventuality transpired when the american government declared war on wietnam.