title: The unidimensional self-efficacy scale for MS (USE-MS): developing a patient based and patient reported outcome.
abstract: BACKGROUND
  Self-efficacy concerns the individual's belief that he or she is capable of performing a certain task and producing a desired effect, i.e. it reflects the person's perceptions of their capability for specific tasks, as distinct from their actual ability. Self-efficacy has been shown to influence motivation, psychological well-being, adherence with treatment regimes and quality of life in multiple sclerosis and other conditions.
  
  
  OBJECTIVE
  To develop a unidimensional scale of MS self-efficacy with robust psychometric properties, suitable for patient self report.
  
  
  METHODS
  A questionnaire pack covering three MS self-efficacy scales, the Dispositional Resilience Scale and demographic data was posted to MS patients from two MS databases. Data underwent Rasch analysis.
  
  
  RESULTS
  Response rate was 309/600 (51.5%). None of the existing MS self-efficacy scales were unidimensional. A new 12-item scale, created by combining items from our two scales, was shown to fit the Rasch model, was unidimensional, and invariant for gender, education and disease duration.
  
  
  CONCLUSIONS
  The Unidimensional Self-Efficacy scale for MS (USE-MS) provides a simple summated scale for an ordinal estimate of a persons' self efficacy. A transformation to interval scaling is available for use in the calculation of change scores and effect sizes.
authors.affiliation: The Walton Centre for Neurology and Neurosurgery, Liverpool, UK. carolyn.young@thewaltoncentre.nhs.uk
authors.forename: C A
authors.initials: CA
authors.lastname: Young
authors.forename: R J
authors.initials: RJ
authors.lastname: Mills
authors.forename: J
authors.initials: J
authors.lastname: Woolmore
authors.forename: C P
authors.initials: CP
authors.lastname: Hawkins
authors.forename: A
authors.initials: A
authors.lastname: Tennant
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D004739:England; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000523:psychology; D011237:Predictive Value of Tests; D011594:Psychometrics; D015203:Reproducibility of Results; D020377:Self Efficacy; D057566:Self Report; D011795:Surveys and Questionnaires