"Back to the Future": Testing the "Individual Problems and Strengths" Scale With a Stepwise Confirmatory Factor...

Routine Outcome Monitoring systems have been developed to monitor how clients' lives change over the course of therapy. However, for such systems to be effective, they must possess sufficient construct validity and scale-reliability to warrant their use. In this study, using a sample of 841 Norwegian clients, we performed the first independent test of the construct validity and scale-reliability of the "Individual Problems and Strengths" (IPS) scale, a subsection of the "Systemic Therapy Inventory of Change." We used a stepwise Confirmatory Factor Analysis approach specifically designed to test the construct validity of the measurement scales. We found satisfactory support for the construct validity of the original "8-factor" version of the IPS; however, its scale reliability received poor to mixed support. Furthermore, we failed to find support for all other previously or recently suggested factorial alternatives to the original 8-factor model. Our analysis leads us to conclude that the developers of the IPS should return "back to the future" by refining their original 8-factor structure of the IPS, while disregarding other proposed versions. TRIAL REGISTRATION: The data stems from an RCT study registered at ClinicalTrials.gov (NCT01873742) as well as from a prior pilot study (Tilden et al. 2015).