title: "When I saw walking I just kind of took it as wheeling": interpretations of mobility-related items in generic, preference-based health state instruments in the context of spinal cord injury.
abstract: BACKGROUND
  In health economic analyses, health states are typically valued using instruments with few items per dimension. Due to the generic (and often reductionist) nature of such instruments, certain groups of respondents may experience challenges in describing their health state. This study is concerned with generic, preference-based health state instruments that provide information for decisions about the allocation of resources in health care. Unlike physical measurement instruments, preference-based health state instruments provide health state values that are dependent on how respondents interpret the items. This study investigates how individuals with spinal cord injury (SCI) interpret mobility-related items contained within six preference-based health state instruments.
  
  
  METHODS
  Secondary analysis of focus group transcripts originally collected in Vancouver, Canada, explored individuals' perceptions and interpretations of mobility-related items contained within the 15D, Assessment of Quality of Life 8-dimension (AQoL-8D), EQ-5D-5L, Health Utilities Index (HUI), Quality of Well-Being Scale Self-Administered (QWB-SA), and the 36-item Short Form health survey version 2 (SF-36v2). Ritchie and Spencer's 'Framework Approach' was used to perform thematic analysis that focused on participants' comments concerning the mobility-related items only.
  
  
  RESULTS
  Fifteen individuals participated in three focus groups (five per focus group). Four themes emerged: wording of mobility (e.g., 'getting around' vs 'walking'), reference to aids and appliances, lack of suitable response options, and reframing of items (e.g., replacing 'walking' with 'wheeling'). These themes reflected item features that respondents perceived as relevant in enabling them to describe their mobility, and response strategies that respondents could use when faced with inaccessible items.
  
  
  CONCLUSIONS
  Investigating perceptions to mobility-related items within the context of SCI highlights substantial variation in item interpretation across six preference-based health state instruments. Studying respondents' interpretations of items can help to understand discrepancies in the health state descriptions and values obtained from different instruments. This line of research warrants closer attention in the health economics and quality of life literature.
authors.affiliation: Department of Health Management and Health Economics, Institute of Health and Society, Medical Faculty, University of Oslo, Postboks 1089, Blindern, 0318, Oslo, Norway.
authors.forename: Yvonne Anne
authors.initials: YA
authors.lastname: Michel
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada.|Centre for Clinical Epidemiology and Evaluation, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.
authors.forename: Lidia
authors.initials: L
authors.lastname: Engel
authors.affiliation: Department of Health Management and Health Economics, Institute of Health and Society, Medical Faculty, University of Oslo, Postboks 1089, Blindern, 0318, Oslo, Norway.|Health Services Research Centre, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Kim
authors.initials: K
authors.lastname: Rand-Hendriksen
authors.affiliation: Department of Health Management and Health Economics, Institute of Health and Society, Medical Faculty, University of Oslo, Postboks 1089, Blindern, 0318, Oslo, Norway.
authors.forename: Liv Ariane
authors.initials: LA
authors.lastname: Augestad
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada. david_whitehurst@sfu.ca.|Centre for Clinical Epidemiology and Evaluation, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada. david_whitehurst@sfu.ca.|International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada. david_whitehurst@sfu.ca.
authors.forename: David Gt
authors.initials: DG
authors.lastname: Whitehurst
mesh_terms: D002170:Canada; D032882:Comprehension; D005260:Female; D017144:Focus Groups; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D051346:Mobility Limitation; D011788:Quality of Life; D013119:Spinal Cord Injuries / Q000523:psychology*; D016138:Walking / Q000523:psychology*; D014910:Wheelchairs / Q000523:psychology
keywords: HRQoL; Item interpretation; Mobility; Preference-based health state instruments; Reframing; Spinal cord injury; Validity