This is my first time posting here, so please forgive me if I am not following some form of etiquette.
My question is in regard to the following evaluation design:
We are examining the impact of policy X. It was implemented at the same time for all units j. We have the ability to collect measurements of A for all participants (i) in a given unit j in both the pre- and post-implementation periods. We do not have a non-treated post-implementation group for comparison, so the following was suggested:
We can match post-participants to the pre-participants on relevant person level factors. Second, to account for historical changes in j-level factors, we can adjust for changes in said factors at level 2 of a hierarchical model.
Overall, our goal would be to estimate an adjusted avearage change in A at the j-level or even estimate what the predicted change would have been when we assume no change in j-level factors.
What are the downsides of this approach?.