title: A casemix model for estimating the impact of hospital access block on the emergency department.
abstract: OBJECTIVE
  To determine the ED activity and costs resulting from access block.
  
  
  METHODS
  A casemix model (AWOOS) was developed to measure activity due to access block. Using data from four hospitals between 1998 and 2002, ED activity was measured using the urgency and disposition group (UDG) casemix model and the AWOOS model with the purpose of determining the change in ED activity due to access block.
  
  
  RESULTS
  Whilst the mean length of stay in ED (admitted patients) increased by 93% between 1998 and 2002, mean UDG activity increased by 0.63% compared to a mean increase in AWOOS activity of 24.5%. The 23.9% difference between UDG and AWOOS activity represents the (unmeasured) increase in ED activity and costs for the period 1998-2002 resulting from access block.
  
  
  CONCLUSIONS
  The UDG system significantly underestimates the activity in EDs experiencing marked access block.
authors.affiliation: Department of Emergency Medicine, Lyell McEwin Health Service, Elizabeth Vale, South Australia, Australia. Peter.Stuart@nwahs.sa.gov.au
authors.forename: Peter
authors.initials: P
authors.lastname: Stuart
mesh_terms: D003953:Diagnosis-Related Groups; D004636:Emergency Service, Hospital / Q000191:economics / Q000706:statistics & numerical data / Q000639:trends*; D005544:Forecasting / Q000379:methods; D017048:Health Care Costs / Q000706:statistics & numerical data; D006297:Health Services Accessibility / Q000191:economics / Q000706:statistics & numerical data / Q000639:trends*; D006779:Hospitals, Public / Q000706:statistics & numerical data; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D015233:Models, Statistical; D010865:Pilot Projects; D013021:South Australia; D014850:Waiting Lists