Porthole
Causal Inference Under Interference In Dynamic Group Therapy Studies (307803)
Lane Burgette, RAND Corporation*Bing Han, RAND Corporation
Susan M. Paddock, NORC
Keywords: Causal inference, interference, mental health, prognostic score
Group therapy is a common treatment modality for behavioral health conditions. Patients often enter and exit groups on an ongoing basis, leading to dynamic therapy groups. Examining the effect of session attendance on patient outcomes is a major research question of interest. However, there are several challenges to identifying causal effects in this setting, including the lack of randomization, interference among patients, and the interrelatedness of patient participation. Dynamic therapy groups motivate a unique causal inference scenario, as the treatment statuses are completely defined by the patient attendance record for the therapy session, which is also the structure inducing interference. We adopt the Rubin Causal Model framework to define the causal effect of high versus low session attendance of group therapy at both the individual patient and peer levels. We propose a strategy to identify individual, peer, and total effects of attendance on patient outcomes, and balance the observed treatment status groups on prognostic score strata. We examine performance of our approach via simulation and apply it to data from a group cognitive behavioral therapy trial for treating d