Abstract
OBJECTIVE: To develop an item response theory (IRT) calibrated Grief and Loss item bank as part of the Spinal Cord Injury--Quality of Life (SCI-QOL) measurement system. DESIGN: A literature review guided framework development of grief/loss. New items were created from focus groups. Items were revised based on expert review and patient feedback and were then field tested. Analyses included confirmatory factor analysis (CFA), graded response IRT modeling and evaluation of differential item functioning (DIF). SETTING: We tested a 20-item pool at several rehabilitation centers across the United States, including the University of Michigan, Kessler Foundation, Rehabilitation Institute of Chicago, the University of Washington, Craig Hospital and the James J. Peters/Bronx Department of Veterans Affairs hospital. PARTICIPANTS: A total of 717 individuals with SCI answered the grief and loss questions. RESULTS: The final calibrated item bank resulted in 17 retained items. A unidimensional model was observed (CFI=0.976; RMSEA=0.078) and measurement precision was good (theta range between -1.48 to 2.48). Ten items were flagged for DIF, however, after examination of effect sizes found this to be negligible with little practical impact on score estimates. CONCLUSIONS: This study indicates that the SCI-QOL Grief and Loss item bank represents a psychometrically robust measurement tool. Short form items are also suggested and computer adaptive tests are available.