Hi all,
Our next virtual meeting will be Wednesday April 8, where we will hear Kosuke
Imai present research on “*Causal Inference with Spatio-temporal Data:
Estimating the Effects of Airstrikes on Insurgent Violence in Iraq*”.
*Abstract*: Although many causal processes have spatial and temporal
dimensions, the classical causal inference framework is not directly
applicable when the treatment and outcome variables are generated by
spatio-temporal point processes. The methodological difficulty primarily
arises from the existence of an infinite number of possible treatment and
outcome event locations at each point in time. In this paper, we consider a
setting where the spatial coordinates of the treatment and outcome events
are observed at discrete time periods. We extend the potential outcomes
framework by formulating the treatment point process as a stochastic
intervention strategy. Our causal estimands include the expected number of
outcome events that would occur in an area of interest under a particular
stochastic treatment assignment strategy. We develop an estimation
technique by applying the inverse probability of treatment weighting method
to the spatially-smoothed outcome surfaces. We show that under a set of
assumptions, the proposed estimator is consistent and asymptotically normal
as the number of time periods goes to infinity. Our motivating application
is the evaluation of the effects of American airstrikes on insurgent
violence in Iraq from February 2007 to July 2008. We consider interventions
that alter the intensity and target areas of airstrikes. We find that
increasing the average number of airstrikes from 1 to 6 per day for seven
consecutive days increases all types of insurgent violence.
*Zoom link*:
https://harvard.zoom.us/j/987462892
*When*: Wednesday, April 8 at 12noon - 1:30pm.
Best,
Georgie