Journal:Journal of Spinal Cord Medicine
Year, Volume, Issue, Page(s):14, 1, 38, 270-287
Article describes the development and calibration of the Spinal Cord Injury -- Quality of Life (SCI-QOL), a patient-reported outcomes measurement system for individuals with spinal cord injury (SCI). Specifically, the authors detail the methods and results of the five phases of the SCI-QOL development: (1) domain/subdomain selection, (2) item development and refinement, (3) field testing, (4) psychometric analysis and item response theory (IRT) calibration, and (5) testing in a new sample to assess of psychometric properties. Individual interviews and focus groups were conducted to select key domains and to develop items for the SCI-QOL. Items were field tested in a sample of 877 individuals with traumatic SCI recruited from 5 SCI Model Systems centers and one Veterans Affairs medical center. Dimensionality was assessed with confirmatory factor analysis. Local item dependence and differential item functioning were assessed, and items were calibrated using IRT methods. Finally, computer adaptive tests (CATs) and short forms were administered in a new sample of 245 individuals with SCI to assess test-retest reliability and stability. Fourteen unidimensional calibrated item banks and 3 calibrated scales were developed across physical, emotional, and social health domains. When combined with the 5 Spinal Cord Injury – Functional Index physical function banks, the final SCI-QOL system consists of 22 IRT-calibrated item banks/scales. Item banks may be administered as CATs or short forms. Scales may be administered in a fixed-length format only.