Hey, I guess randomized designs are not feasible in our hospital. Could you please give us some suggestions under the current situation?

Our pleasure.

I see. Thanks.

In this case, it is critical to determine how the participating practices chose (or were chosen) to participate in the intervention and mimic those factors to the extent possible when selecting a nonexperimental comparison group. The factors driving participation include formal and informal selection criteria by the organization and decisions made by practices. For example, if the organization selects all practices in a particular city to test the intervention, the comparison group should contain practices in a city with a comparable market and patient mix. If only practices that had certain health IT in place were chosen, practices with similar health IT, as well as size, patient mix, and outcomes—before the intervention—should be selected for the comparison group. Ideally, the group of comparison practices should have the same characteristics as the intervention practices. Two popular options for selecting a comparison group are regression discontinuity (RD) designs, and propensity score matching (PSM) designs. However, both PSM and RD designs may not have sufficient power for interventions with a small number of practices.