Factor structure and validity of the Therapeutic Factors Inventory–Short Form.

Clinical group practice is commonly guided by the assumption that 11 distinct therapeutic factors operate in psychotherapy groups. This assumption should be closely examined due to the emerging evidence of fewer, more global therapeutic factors. The present study was conducted to continue the development of the Therapeutic Factors Inventory–Short Form (TFI–S) and focused on confirming its factor structure and evaluating aspects of its concurrent, discriminant, and predictive validity. A sample comprising a total of 435 clients from 52 distinct therapy groups at eight different clinical sites in the U.S. and Canada was obtained. Structural equation modeling analyses indicated that a fourfactor model had a reasonably good fit to the TFI–S rating data, and it provided indications for further refinement of the constituent items. The analyses resulted in a revised, 19-item measure, the Therapeutic Factors Inventory–19 (TFI–19). Three-level HLM analyses demonstrated that the four factors were sensitive to change in member perceptions over time. Significant and meaningful relationships between the TFI–19 factors and subscales of the Group Climate Questionnaire-Short Form provided support for the concurrent validity of the TFI–19. Two-level HLM analyses identified significant relationships between the TFI–19 factors and posttreatment status on symptomatic and interpersonal distress, thereby supporting the predictive validity of the TFI–19. The findings suggest that the TFI–19 may be a useful instrument to assess group members’ perceptions of more global therapeutic factors.