title: Construct validity of the Assessment of Quality of Life - 6D (AQoL-6D) in community samples.
abstract: BACKGROUND
  The Assessment of Quality of Life - 6D scale (AQoL-6D) is a self-report instrument designed to provide a sensitive multidimensional evaluation of health related quality of life. The current paper assesses the construct, concurrent and convergent validity of the AQoL-6D in a combined longitudinal population sample drawn from across urban, regional and remote areas of Australia.
  
  
  METHODS
  The AQoL-6D was administered within the Hunter Community Study and the Australian Rural Mental Health Study over time (mean years lag = 3.90, SD = 1.30). Observations with sufficient data were used to confirm the construct validity of the AQoL-6D domains and higher-order structure using confirmatory factor analyses (CFA, N = 7915). The stability of this structure across cohorts and over time was assessed using multi-group CFA. Additionally, the concurrent validity (against the SF-36) and convergent validity of AQoL-6D domains and factors were assessed.
  
  
  RESULTS
  The construct validity of the AQoL-6D domains was considered satisfactory. Two higher-order factors, representing the physical and psychological components of quality of life were identified (CFA model fit: RMSEA = .07, SRMR = .03; TLI = .96, CFI = .98). These factors displayed group and temporal invariance, as well as concurrent and convergent validity against a range of measures. Recommendations for the derivation of summary scores are provided, together with a provisional set of norms.
  
  
  CONCLUSIONS
  The AQoL-6D is a useful tool for assessing quality of life impairment in epidemiological cohort studies, both cross-sectionally and over time. It displays appropriate levels of construct, concurrent and convergent validity. Conceptualisation of higher-order factors as representing the physical and psychological aspects of quality of life impairment may increase the sensitivity and appeal of the AQoL-6D, particularly for studies examining predictors of and changes in social and psychological outcomes.
authors.affiliation: Centre for Translational Neuroscience and Mental Health, University of Newcastle and Hunter New England Health, Newcastle, NSW, Australia. Joanne.Allen@newcastle.edu.au
authors.forename: Joanne
authors.initials: J
authors.lastname: Allen
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Inder
authors.forename: Terry J
authors.initials: TJ
authors.lastname: Lewin
authors.forename: John R
authors.initials: JR
authors.lastname: Attia
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Kelly
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001315:Australia; D015331:Cohort Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D015203:Reproducibility of Results; D012424:Rural Population / Q000706:statistics & numerical data; D017678:Sex Distribution; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards*; D013996:Time and Motion Studies; D014505:Urban Population / Q000706:statistics & numerical data