title: The Impact on Life questionnaire: validation for elective surgery prioritisation in New Zealand prioritisation criteria in orthopaedic surgery.
abstract: OBJECTIVE
  This cohort study tested the reliability and validity of the Impact on Life (IoL) patient-rated questionnaire for use in prioritising orthopaedic procedures.
  
  
  METHODS
  Three hundred and twenty-four patients completed the questionnaire during specialist orthopaedic assessments over a 5-month period in 2013. The reliability and validity of the IoL were tested against the SF-12 and Oxford scores. Correlation analysis was used to assess patient- and surgeon-rated scores. Internal consistency reliability was assessed using Cronbach's alpha. Patient- and surgeon-rated scores were further analysed between patients added to the waiting list and those that were not.
  
  
  RESULTS
  Participants' mean age was 58 years (range 18-88). Reliability analysis showed the IoL had excellent internal consistency with a Cronbach's alpha of 0.926, reaching the threshold for clinical application. Construct validity of the IoL was confirmed with significant correlation with other validated quality of life measures (p&lt;0.01). T-tests indicated that patients placed on the waiting list had significantly higher surgeon and IoL scores (p&lt;0.001), compared with those not placed on the waiting list.
  
  
  CONCLUSIONS
  Our results support the IoL as a valid and reliable method of assessing patient-rated quality of life and recommend its use in the Orthopaedic Clinical Priority Assessment Criteria score.
authors.forename: Georgina
authors.initials: G
authors.lastname: Chan
authors.forename: Louret
authors.initials: L
authors.lastname: Bezuidenhout
authors.forename: Logan
authors.initials: L
authors.lastname: Walker
authors.affiliation: Wellington Hospital, Riddiford Street, Newtown, Wellington 6035. robert.rowan@ccdhb.org.nz.
authors.forename: Robert
authors.initials: R
authors.lastname: Rowan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017558:Elective Surgical Procedures / Q000706:statistics & numerical data*; D005260:Female; D006292:Health Priorities; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D019637:Orthopedic Procedures / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult