Does anyone have any experience using propensity weighting schemes such as IPTW (Inverse Probability of Treatment Weighting) estimation? I have a model that uses IPTW to estimate the Average Treatment Effect from observational data, but I'm not sure how to interpret the results or test the significance.
It's a (sorta) controlled experiment, so we actually have access to the real propensity scores. The procedure goes like this:
Assign individuals to treatment with some probability
Weight the outcomes for each individual based on the inverse of the probability of treatment (propensity score)
Compare the mean outcomes of treatment and control groups to form ATE
Now I have the ATE, but I don't know how to test my null (i.e. P(ATE <= 0)). Does anyone have any idea how this is done usually?