Our first meeting of the spring semester will be at 12pm (EST) Wednesday, January 27 (tomorrow), where we will hear Guillaume Basse (Stanford University) presents research on "Displacement Effects in a Hot Spot Policing Intervention in Medellin: Inference and Pitfalls."

In hot policing, resources are targeted at specific locations predicted to be at high risk of crime; so-called "hot spots." Rather than reduce overall crime, however, there is a concern that these interventions simply displace crime from the targeted locations to nearby non-hot spots. We address this question in the context of a large-scale randomized experiment in Medellin, Colombia, in which police were randomly assigned to increase patrols at a subset of possible hotspots. Estimating the displacement effects on control locations is difficult because the probability that a nearby hotspot is treated is a complex function of the underlying geography. While existing methods developed for this "general interference" setting, especially Horvitz-Thompson (HT) estimators, have attractive theoretical properties, they can perform poorly in practice and mislead practitioners. In this talk, I explore the key pitfalls that practitioners should watch out for when conducting this type of analysis, and propose some ways to partially remedy them.

Looking forward to seeing you all tomorrow!

Best,

Soichiro