title: On the Hospital Volume and Outcome Relationship: Does Specialization Matter More Than Volume?
abstract: OBJECTIVE
  To evaluate the relationship between hospital volume and outcome by focusing on alternative measures of volume that capture specialization and overall throughput of hospitals.
  
  
  METHODS
  Hospital administrative data from the state of Victoria, Australia; data contain 1,798,474 admitted episodes reported by 135 public and private acute-care hospitals.
  
  
  METHODS
  This study contrasts the volume-outcome relationship using regression models with different measures of volume; two-step and single-step risk-adjustment methods are used.
  
  
  METHODS
  The sample is restricted to ischemic heart disease (IHD) patients (ICD-10 codes: I20-I25) admitted during 2001/02 to 2004/05.
  
  
  RESULTS
  Overall hospital throughput and degree of specialization display more substantive implications for the volume-outcome relationship than conventional caseload volume measure. Two-step estimation when corrected for heteroscedasticity produces comparable results to single-step methods.
  
  
  CONCLUSIONS
  Different measures of volume could lead to vastly different conclusions about the volume-outcome relationship. Hospital specialization and throughput should both be included as measures of volume to capture the notion of size, focus, and possible congestion effects.
authors.affiliation: Golden Dragon Centre, City University of Macau, Macau, China.|Faculty of Business and Economics, University of Melbourne, Melbourne, VIC, Australia.
authors.forename: Kris C L
authors.initials: KC
authors.lastname: Lee
authors.affiliation: Melbourne Business School, University of Melbourne, Carlton, VIC, Australia.
authors.forename: Kannan
authors.initials: K
authors.lastname: Sethuraman
authors.affiliation: Faculty of Business and Economics, University of Melbourne, Melbourne, VIC, Australia.
authors.forename: Jongsay
authors.initials: J
authors.lastname: Yong
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D017052:Hospital Mortality; D061847:Hospitals, High-Volume / Q000706:statistics & numerical data*; D006782:Hospitals, Special / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000401:mortality / Q000628:therapy*; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D010067:Ownership; D011787:Quality of Health Care / Q000706:statistics & numerical data*; D020379:Risk Adjustment; D012737:Sex Factors; D012959:Socioeconomic Factors; D014739:Victoria
keywords: Hospital volume and outcome; hospital quality; risk adjustment; specialization