Clinimetric Properties of the Working Alliance Inventory and Credibility Expectancy Questionnaire: Screening Options for Musculoskeletal Pain

To investigate clinimetric properties of 2 surveys used to evaluate common factors in the patient-provider relation and present screener options for the assessment of common factors and report their correlation with pain and functional outcomes. Observational cohort. Outpatient physical therapy. 100 individuals (58% women, mean age=34, SD=15; N=100) presenting to physical therapy with musculoskeletal pain in the following regions: 44% lower extremity, 36% spine, 19% upper extremity, 1% undetermined. Not applicable. Participants completed the Working Alliance Inventory (WAI) and the Credibility and Expectancy Questionnaire (CEQ). Exploratory factor analysis (EFA) explored factor structure of the WAI and CEQ. Internal consistency was evaluated for scales derived from items retained based on factor loadings. Finally, options for screener tools were proposed and assessed based on their correlation to original surveys as well as pain and functional outcomes. The data supported a 4-factor structure for the surveys. Some WAI items were excluded due to cross-loading. The derived four-factor scales demonstrated strong correlations with the original surveys (r=.89-.99) and exhibited good internal consistency (α=.824-.875). Two screening options were suggested: 1 retaining 11 of the original 18 items and the other comprising just 3 items. Both screening tools correlated with the original surveys and showed associations with improvements in pain and functional outcomes (r=-.21-.34). The proposed screeners provide concise measurement options to facilitate use in clinical practice. These tools can aid in facilitating patient communication specifically addressing patient expectation and understanding the tasks required to enact behavior change.