title: The Health of the Nation Outcome Scales: validating factorial structure and invariance across two health services.
abstract: OBJECTIVE
  The Health of the Nation Outcome Scale (HoNOS) was developed in the mid-1990s as an inclusive and comprehensive instrument to measure patient outcomes in four main factors: behaviour, impairment, symptoms and social problems. This paper attempts to investigate whether similar health services rate the HoNOS with equivalent psychometric calibration.
  
  
  METHODS
  The purpose of this study was to test for invariant construct interpretation of the instrument across two equivalent health services, using simultaneous confirmatory factor analysis.
  
  
  RESULTS
  Although the four-factor model of the HoNOS was confirmed, structural non-invariance occurred, casting doubt on the equivalent interpretability and generalisability of the instrument across similar heath services.
  
  
  CONCLUSIONS
  Over-inclusiveness, lack of specificity and questionable independence of observations may have contributed to the non-invariant factor structure between the two health services. Such results shed some doubt on the ability of the HoNOS and like observational instruments to provide equivalent comparisons between health services.
authors.affiliation: Mental Health Services, Fremantle Hospital and Health Service, Western Australia, Australia. neil.preston@health.wa.gov.au
authors.forename: N J
authors.initials: NJ
authors.lastname: Preston
mesh_terms: D000328:Adult; D002391:Catchment Area, Health; D005163:Factor Analysis, Statistical; D005260:Female; D006760:Hospitalization; D006778:Hospitals, Psychiatric; D006801:Humans; D007902:Length of Stay; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000534:rehabilitation*; D008605:Mental Health Services / Q000592:standards*; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome