title: Metric properties of the Spinal Cord Independence Measure - Self Report in a community survey.
abstract: OBJECTIVE
  The Spinal Cord Independence Measure - Self Report (SCIM-SR) is a self-report instrument for assessing functional independence of persons with spinal cord injury. This study examined the internal construct validity and reliability of the SCIM-SR, when administered in a community survey, using the Rasch measurement model.
  
  
  METHODS
  Rasch analysis of data from 1,549 individuals with spinal cord injury who completed the SCIM-SR.
  
  
  RESULTS
  In the initial analysis no fit to the Rasch model was achieved. Items were grouped into testlets to accommodate the substantial local dependency. Due to the differential item functioning for lesion level and degree, spinal cord injury-specific sub-group analyses were conducted. Fit to the Rasch model was then achieved for individuals with tetraplegia and complete paraplegia, but not for those with incomplete paraplegia. Comparability of ability estimates across sub-groups was attained by anchoring all sub-groups on a testlet.
  
  
  CONCLUSIONS
  The SCIM-SR violates certain assumptions of the Rasch measurement model, as shown by the local dependency and differential item functioning. However, an intermediate solution to achieve fit in 3 out of 4 spinal cord injury sub-groups was found. For the time being, therefore, it advisable to use this approach to compute Rasch-transformed SCIM-SR scores.
authors.affiliation: ICF Unit, Swiss Paraplegic Research, CH-6207 Nottwil, Switzerland. E-mail: birgit.prodinger@paraplegie.ch.
authors.forename: Birgit
authors.initials: B
authors.lastname: Prodinger
authors.forename: Carolina S
authors.initials: CS
authors.lastname: Ballert
authors.forename: Martin W G
authors.initials: MW
authors.lastname: Brinkhof
authors.forename: Alan
authors.initials: A
authors.lastname: Tennant
authors.forename: Marcel W M
authors.initials: MW
authors.lastname: Post
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000071066:Patient Reported Outcome Measures; D015203:Reproducibility of Results; D057566:Self Report; D013119:Spinal Cord Injuries / Q000523:psychology* / Q000534:rehabilitation; D011795:Surveys and Questionnaires