title: Establishing thresholds for adverse patient outcomes.
abstract: OBJECTIVE
  To establish thresholds for adverse patient outcomes in the absence of knowledge of patient illness severity indices.
  
  
  RESULTS
  Pulmonary embolism, unplanned return to operating rooms, unplanned readmissions, clean and contaminated wound infections, and hospital-acquired bacteraemia.
  
  
  METHODS
  Analysis of results of surveys of hospitals in Australia by the Australian Council on Healthcare Standards following the introduction of clinical performance measures into the Accreditation process.
  
  
  METHODS
  Acute care hospitals in Australia undergoing Accreditation surveys in 1993 and 1994.
  
  
  METHODS
  Stratification of hospitals into small (1-99 beds), medium (100-199 beds), and large (> or = 200 beds), calculation of mean rates for the above outcomes in each group, and establishment of thresholds based on two standard errors from the mean.
  
  
  RESULTS
  The mean rate of occurrence of incidents was higher for larger hospitals. Thresholds were generally lower for smaller and higher for larger hospitals.
  
  
  CONCLUSIONS
  Bed-size is a useful index for "flagging" peer group variation. The methodological issues in establishing thresholds and their implications in monitoring the quality of care in hospitals are discussed.
authors.affiliation: ACHS Care Evaluation Program (CEP), Australia.
authors.forename: M Z
authors.initials: MZ
authors.lastname: Ansari
authors.forename: B T
authors.initials: BT
authors.lastname: Collopy
authors.forename: I G
authors.initials: IG
authors.lastname: McDonald
mesh_terms: D000068:Accreditation / Q000592:standards*; D001315:Australia / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology; D019538:Health Care Surveys; D006742:Hospital Bed Capacity; D006761:Hospitals / Q000592:standards* / Q000706:statistics & numerical data; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000592:standards*; D010359:Patient Readmission / Q000706:statistics & numerical data; D011182:Postoperative Care / Q000592:standards*; D011655:Pulmonary Embolism / Q000209:etiology; D012086:Reoperation / Q000706:statistics & numerical data; D012720:Severity of Illness Index; D013530:Surgical Wound Infection / Q000453:epidemiology