title: Translation, data quality, reliability, validity and responsiveness of the Norwegian version of the Effective Musculoskeletal Consumer Scale (EC-17).
abstract: BACKGROUND
  The Effective Musculoskeletal Consumer Scale (EC-17) is a self-administered questionnaire for evaluating self-management interventions that empower and educate people with rheumatic conditions. The aim of the study was to translate and evaluate the Norwegian version of EC-17 against the necessary criteria for a patient-reported outcome measure, including responsiveness to change.
  
  
  METHODS
  Data quality, reliability, validity and responsiveness were assessed in two groups. One group comprising 103 patients received a questionnaire before and at the end of a self-management programme. The second group comprising 96 patients' received the questionnaire two weeks before and on arrival of the program. Internal consistency and test-retest reliability were assessed. Construct validity was assessed through comparisons with the Brief Approach/Avoidance Coping Questionnaire, (BACQ), the Emotional Approach Coping Scale (EAC) and the General Health Questionnaire (GHQ-20). Responsiveness was assessed with the Standardised Response Mean (SRM).
  
  
  RESULTS
  Respondents included 66 (64%) and 52 (54%) patients from the first and second groups respectively. Levels of missing data were low for all items. There was good evidence for unidimensionality, item-total correlations ranged from 0.59 to 0.82 and Cronbach's Alpha and test-retest correlations were over 0.90. As hypothesised EC-17 scores had statistically significant low to moderate correlations with the BACQ, EAC and GHQ-20 in the range 0.26 to 0.42. Following the self-management program, EC-17 scores showed a significant improvement with an SRM of 0.48.
  
  
  CONCLUSIONS
  The Norwegian version of the EC-17 has evidence for data quality, internal consistency and test-retest reliability, construct validity and responsiveness to change. The EC-17 seems promising as an outcome measure for evaluating self-management interventions for people with rheumatic conditions, but further studies are needed.
authors.affiliation: Hospital for Rheumatic Diseases, M. Grundvigsvei 6, Lillehammer, Norway. bente.hamnes@revmatismesykehuset.no
authors.forename: Bente
authors.initials: B
authors.lastname: Hamnes
authors.forename: Andrew
authors.initials: A
authors.lastname: Garratt
authors.forename: Ingvild
authors.initials: I
authors.lastname: Kjeken
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kristjansson
authors.forename: Kåre B
authors.initials: KB
authors.lastname: Hagen
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000517:prevention & control / Q000534:rehabilitation*; D009664:Norway; D017063:Outcome Assessment, Health Care / Q000379:methods; D010342:Patient Acceptance of Health Care; D010349:Patient Compliance; D010353:Patient Education as Topic / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012216:Rheumatic Diseases / Q000517:prevention & control / Q000534:rehabilitation*; D011795:Surveys and Questionnaires / Q000592:standards*; D014175:Translating