Multi-group measurement invariance of the multiple sclerosis walking scale-12?

Robert W. Motl, Sean Mullen, Edward Mcauley

Research output: Contribution to journalArticlepeer-review


Objective: One primary assumption underlying the interpretation of composite multiple sclerosis walking scale-12 (MSWS-12) scores across levels of disability status is multi-group measurement invariance. This assumption was tested in the present study between samples that differed in self-reported disability status. Method: Participants (n=867) completed a battery of questionnaires that included the MSWS-12 and patient-determined disease step (PDDS) scale. The multi-group invariance was tested between samples that had PDDS scores of ≤2 (i.e. no mobility limitation; n=470) and PDDS scores ≥3 (onset of mobility limitation; n=397) using Mplus 6.0. Results: The omnibus test of equal covariance matrices indicated that the MSWS-12 was not invariant between the two samples that differed in disability status. The source of non-invariance occurred with the initial equivalence test of the factor structure itself. Conclusion: We provide evidence that questions the unambiguous interpretation of scores from the MSWS-12 as a measure of walking impairment between samples of persons with multiple sclerosis who differ in disability status.

Original languageEnglish (US)
Pages (from-to)149-152
Number of pages4
JournalNeurological Research
Issue number2
StatePublished - Mar 2012


  • Multiple sclerosis
  • Validity
  • Walking

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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