title: The SF-36 physical and mental health factors were confirmed in cancer and HIV/AIDS patients.
abstract: OBJECTIVE
  This study assesses the extent to which the RAND-36/SF-36 items measure physical and mental health (PH and MH), as implied by existing summary scoring systems.
  
  
  METHODS
  A total of 1,714 heterogeneous cancer and HIV/AIDS patients were recruited from five institutions. Of these, 56% were women; 81% Caucasians; and about 10% were from each of the major cancer types and HIV/AIDS.
  
  
  RESULTS
  Analyses of the SF-36 confirmed the two dimensions of health namely physical and mental. However, item fit statistics and residual factor analysis revealed that some items intended to represent the PH dimension fit better with the MH dimension.
  
  
  CONCLUSIONS
  This paper demonstrated the value of Rasch residual factor analysis for understanding and enhancing interpretation of health.
authors.affiliation: Buehler Center on Aging, Institute for Healthcare Studies, Division of General Internal Medicine, and Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. chchang@northwestern.edu
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Chang
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Wright
authors.forename: David
authors.initials: D
authors.lastname: Cella
authors.forename: Ron D
authors.initials: RD
authors.lastname: Hays
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001294:Attitude to Health; D005163:Factor Analysis, Statistical; D005260:Female; D015658:HIV Infections / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D009369:Neoplasms / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D011594:Psychometrics; D011788:Quality of Life