Psychometric Properties of the Satisfaction With Life Scale in People With Traumatic Brain, Spinal Cord, or Burn Injury: A National Institute on Disability, Independent Living, and Rehabilitation Research Model System Study. (June 2019)

• Record Type: Journal Article
• Authors: Amtmann, Dagmar; Bocell, Fraser D.; Bamer, Alyssa; Heinemann, Allen W.; Hoffman, Jeanne M.; Juengst, Shannon B.; Rosenberg, Marta; Schneider, Jeffery C.; Wiechman, Shelley; McMullen, Kara
• Is Part Of: Assessment. Volume 26:Number 4(2019)
• Page Start: 695
• Page End: 705
• Publication Date: 2019-06
• Subjects: measurement invariance -- item response theory -- Satisfaction With Life Scale -- traumatic brain injury -- spinal cord injury -- burn injury; Psychological tests -- Periodicals; Psychodiagnostics -- Periodicals; Personality tests -- Periodicals; 150.287
• DOI: 10.1177/1073191117693921
• Languages: English
• ISSNs: 1073-1911

Abstract

This study evaluated the measurement properties of the Satisfaction With Life Scale (SWLS) in a sample of 17, 897 people with spinal cord injury (48%, n = 8, 566), traumatic brain injury (44%, n = 7, 941), and burn injury (8%, n = 1, 390), 1 year following injury. We examined measurement invariance across the groups, unidimensionality, local independence, reliability from a classical test and item response theory (IRT) framework, and fit to a unidimensional IRT model. The results support unidimensionality and local independence of the SWLS. Reliability was adequate from a classical test and IRT perspective. IRT analysis found that the SWLS could be improved by using only five response categories rather than seven and by removing the fifth item, "If I could live my life over, I would change almost nothing." This item functions poorly and reduces instrument reliability. With these revisions, the SWLS is a useful instrument to monitor an important outcome of trauma rehabilitation.