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

Assessment, 2019 · DOI: 10.1177/1073191117693921 · Published: June 1, 2019

Simple Explanation

This study examines the Satisfaction With Life Scale (SWLS) in individuals with spinal cord injury (SCI), traumatic brain injury (TBI), and burn injury (BI). It aims to understand if the scale measures life satisfaction consistently across these different injury groups. The research uses statistical methods to assess the scale's reliability and validity in these populations. This includes checking if the scale functions the same way across the three injury groups and identifying potential areas for improvement. The findings suggest that the SWLS is generally adequate for measuring life satisfaction in these groups but could be improved by reducing the number of response options and removing one problematic item.

Study Duration

Not specified

Participants

17,897 people with spinal cord injury, traumatic brain injury, and burn injury

Evidence Level

Not specified

Key Findings

1
The SWLS functions similarly across SCI, TBI, and BI populations, supporting comparisons between these groups.
2
The SWLS items measure a single construct, allowing for the use of a single summary score.
3
The scale could be improved by using five rather than seven response options, and by removing Item 5.

Research Summary

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. With these revisions, the SWLS is a useful instrument to monitor an important outcome of trauma rehabilitation.

Practical Implications

Improved Scale Utility

Revising the SWLS based on study findings can lead to a more accurate and efficient measure of life satisfaction.

Enhanced Comparability

Ensuring measurement invariance allows for meaningful comparisons of life satisfaction across different traumatic injury populations.

Informed Clinical Practice

Understanding the psychometric properties of the SWLS can help clinicians better interpret and use the scale in rehabilitation settings.

Study Limitations

1
No evidence for the validity of the SWLS scores was collected or evaluated during this study.
2
The samples used in the current study were unbalanced, with fewer cases with BI than either SCI or TBI.
3
The samples for each of the injury types, SCI, TBI, and BI, are not necessarily representative of the larger population of individuals with such injuries

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