Preliminary Evaluation of an Observational Measure of Group Cohesion for Group Psychotherapy


  • This research was supported by NIMH grant 1R03MH079019 to Amori Mikami and a Jefferson Graduate Research Fellowship from the Jefferson Scholars Foundation to Matthew D. Lerner.

  • We would like to thank the children, parents, and teachers who participated, and the schools and doctors who provided referrals for this study. We are grateful to the graduate students who served as therapists on this project, as well as to the undergraduate coders who committed many hours to collecting the alliance data.

Please address correspondence to: Matthew D. Lerner, 102 Gilmer Hall Box 400400, Charlottesville, VA, 22904-4400. E-mail:



Group psychotherapy research would benefit from an observational measure of group cohesion to complement existing self-report measures. This study introduces the Therapy Process Observational Coding System-Group Cohesion scale (TPOCS-GC), which observationally assesses cohesion between each member and the group.


In total 27 parents participated in a group parent-training social competency intervention for children with attention deficit-hyperactivity disorder. Independent coders double-coded group cohesion and the alliance in 144 client-sessions. Parents, teachers, and children completed cognitive, behavioral, and therapy participation measures.


The TPOCS-GC demonstrated modest to strong item-level interrater reliability and acceptable internal consistency. Group cohesion evidenced moderate stability over the course of treatment. Relations between TPOCS-GC and theoretically linked and unrelated variables provided some evidence for construct and predictive validity.


This preliminary study suggests that the TPOCS-GC is a reliable instrument that may help fill an instrumentation gap in the field.