Many empirical questions can be cast as inference on a parameter selected through optimization. For example, researchers may be interested in the effectiveness of the best policy found in a randomized trial, or the best-performing investment strategy based on historical data. Such settings give...

We estimate the impact of piped water and sewers on property values in mid-19th century Chicago. The cost of sewer construction depends sensitively on imperceptible variation in grade, and such variations in grade delay water and sewer service to part of the city. This delay provides...

We investigate the effects of sewer access on neighborhood characteristics in developing world cities. Because it is more difficult to move sewage uphill than downhill, otherwise similar neighborhoods on opposite sides of drainage basin divides may face different costs of sewer access. We...

We develop an optimal policy assignment rule that integrates two distinctive approaches commonly used in economics--targeting by observables and targeting through self-selection. Our method can be used with experimental or quasi-experimental data to identify who should be treated, be untreated,...

Economic policies often involve dynamic interventions, where individuals receive repeated interventions over multiple periods. This dynamics makes past responses informative to predict future responses and ultimate outcomes depend on the history of interventions. Despite these phenomena,...