Development, Content Validity, and Reliability of the Physical Therapy Social Determinants of Health Scale.

Abstract

Introduction: This study describes the development, content validity, and reliability of the Physical Therapy Social Determinants of Health Scale (PT-SDHS), in Doctor of Physical Therapy (DPT) students.

Review of literature: Addressing inequities stemming from the social determinants of health (SDOH) is critical for providing effective clinical care and improving population health. Currently, no tool exists to assess DPT students' education or competence with SDOH.

Subjects: Recruited domain experts were licensed health professionals, had a peer-reviewed publication on SDOH, and had at least 3 years of experience with SDOH. A convenience sample of DPT students was also recruited from multiple cohorts at 2 universities in multiple geographic locations.

Methods: The Association for Medical Education in Europe best practices for developing questionnaires for educational research guided development of the PT-SDHS. Eight experts established content validity through item- and scale-content validity index measures and modified Kappa statistics. Qualitative data determined clarity and comprehensiveness. Construct validity and scale reliability were determined using exploratory factor analysis and Cronbach's alpha.

Results: The PT-SDHS showed high item content validity (range: 0.86-1) and scale content validity (S-CVI/UA = 0.83; S-CVI/Ave = 0.98). After expert validation, the PT-SDHS consisted of 30 items with 5 ordinal answer choices. Factor analysis of 254 DPT student responses revealed 4 content domains with a factor loading greater than 0.4. Two items did not load onto any of the factors, and 2 items were cross-loaded onto multiple factors, so they were removed, leaving a scale of 26 items. Cronbach's alpha ranged from 0.74 (satisfactory) to 0.96 (excellent) across the 4 factors.

Discussion and conclusion: The PT-SDHS is the first psychometrically valid and reliable instrument related to educating DPT students on 4 SDOH domains: Knowledge, Attitudes, Personal Barriers, and Beliefs About Others. This tool could aid development and assessment of SDOH educational interventions for health care students.