Article

OBJECTIVE: To evaluate the metric properties of distinct measures of
psychological personal factors comprising feelings, beliefs, motives, and
patterns of experience and behaviour assessed in the Swiss Spinal Cord Injury
Cohort Study (SwiSCI), using Rasch methodology.
METHODS: SwiSCI Pathway 2 is a community-based, nationwide, cross-sectional survey for persons with spinal cord
injury (SCI) (n = 511). The Rasch partial credit model was used for each subscale
of the Positive Affect Negative Affect Scale (PANAS), Appraisal of Life Events
Scale (ALE), Purpose in Life test - Short Form (PIL-SF), and the Big Five
Inventory-K (BFI-K). RESULTS: The measures were unidimensional, with the
exception of the positive affect items of the PANAS, where pairwise t-tests
resulted in 10% significant cases, indicating multidimensionality. The BFI-K
subscale agreeableness revealed low reliability (0.53). Other reliability
estimates ranged between 0.61 and 0.89. Ceiling and floor effects were found for
most measures. SCI-related differential item functioning (DIF) was rarely found.
Language DIF was identified for several items of the BFI-K, PANAS and the ALE,
but not for the PIL-SF. CONCLUSION: A majority of the measures satisfy the
assumptions of the Rasch model, including unidimensionality. Invariance across
language versions still represents a major challenge.

Langue : ANGLAIS