title: Confirmatory factor analysis of the Work Limitations Questionnaire (WLQ-25) in Workers' Compensation Claimants with chronic upper-limb disorders.
abstract: OBJECTIVE
  To examine the factorial validity of the Work Limitations Questionnaire (WLQ-25) among workers' compensation claimants with chronic upper-limb disorders.
  
  
  METHODS
  Attendees of the WSIB Shoulder and Elbow Specialty clinic in Toronto, Ontario, Canada, completed a survey that includes the WLQ-25 [4 subscales: time-management (TM), physical demands (PD), mental-interpersonal (MI), and output demands (OD)]. Confirmatory factor analyses (n = 2262) were conducted to evaluate and compare alternative 4- and 5-factor WLQ-25 structures [MI subscale intact vs. separated into mental demands (MD) and interpersonal demands (IP) subscales]. Model fit indices, saliency of factor loadings, and convergent/divergent validity of latent factors (r = 0.4 - 0.85 expected) were concurrently assessed.
  
  
  RESULTS
  The 4-factor WLQ-25 showed acceptable model fit after allowing the residuals of a pair of PD items to correlate (CFI = 0.924, TLI = 0.915, RMSEA = 0.057, SRMR = 0.054); however, significantly lower-than-expected correlations between the PD factor and all other factors (r = -0.11 - -0.03) were also observed. Model fit for the 5-factor WLQ-25 was even more optimal (CFI = 0.934, TLI = 0.925, RMSEA = 0.053, SRMR = 0.051), with MD and IP factors correlating at r = 0.83.
  
  
  CONCLUSIONS
  Evidence of factorial validity was demonstrated by the WLQ-25; however, users should be attentive of an instrumentation issue that could be directly related to the psychometric performance of its PD subscale.
authors.affiliation: Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada. ken.tang@mail.utoronto.ca
authors.forename: Kenneth
authors.initials: K
authors.lastname: Tang
authors.forename: Dorcas E
authors.initials: DE
authors.lastname: Beaton
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Amick
authors.forename: Sheilah
authors.initials: S
authors.lastname: Hogg-Johnson
authors.forename: Pierre
authors.initials: P
authors.lastname: Côté
authors.forename: Patrick
authors.initials: P
authors.lastname: Loisel
mesh_terms: D000328:Adult; D002170:Canada; D002908:Chronic Disease; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario; D011594:Psychometrics / Q000295:instrumentation* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards*; D034941:Upper Extremity / Q000503:physiopathology*; D014938:Work Capacity Evaluation; D014942:Workers' Compensation