title: American Medical Association impairment ratings and earnings losses due to disability.
abstract: OBJECTIVE
  To examine the association between impairment ratings and earnings losses.
  
  
  METHODS
  We conducted a case-control study of 21,663 workers' compensation claimants in California with impairment ratings under the AMA Guides, fifth edition. Earnings losses represented the percent difference between the earnings of cases and controls 3 years after disability onset.
  
  
  RESULTS
  Impairment ratings were strongly associated with earnings losses: losses for ratings of 1, 10, and 20 were 9.0%, 21.9%, and 34.6%, respectively (P < 0.01). Losses differed significantly across body regions. For example, losses were 21.0% for spine impairments compared with 18.4% overall (P = 0.014).
  
  
  CONCLUSIONS
  Impairment ratings are accurate predictors of disability severity on average, but their ability to measure disability could be improved with additional information on how the relationship between ratings and earnings loss varies according to patient and injury characteristics.
authors: RAND Corporation, Santa Monica, CA 90407, USA. seabury@rand.org
authors: Seth A
authors: SA
authors: Seabury
authors: Frank
authors: F
authors: Neuhauser
authors: Teryl
authors: T
authors: Nuckols
mesh_terms: D000328:Adult; D002140:California; D016022:Case-Control Studies; D017281:Cost of Illness; D004185:Disability Evaluation; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D016555:Matched-Pair Analysis; D008875:Middle Aged; D015999:Multivariate Analysis; D060051:Occupational Injuries / Q000175:diagnosis / Q000191:economics*; D017410:Practice Guidelines as Topic; D012044:Regression Analysis; D012955:Societies, Medical; D014942:Workers' Compensation / Q000191:economics / Q000706:statistics & numerical data