title: Comparison of three methods for estimating rates of adverse events and rates of preventable adverse events in acute care hospitals.
abstract: OBJECTIVE
  To compare the effectiveness, reliability, and acceptability of estimating rates of adverse events and rates of preventable adverse events using three methods: cross sectional (data gathered in one day), prospective (data gathered during hospital stay), and retrospective (review of medical records).
  
  
  METHODS
  Independent assessment of three methods applied to one sample.
  
  
  METHODS
  37 wards in seven hospitals (three public, four private) in southwestern France.
  
  
  METHODS
  778 patients: medical (n = 278), surgical (n = 263), and obstetric (n = 237).
  
  
  METHODS
  The main outcome measures were the proportion of cases (patients with at least one adverse event) identified by each method compared with a reference list of cases confirmed by ward staff and the proportion of preventable cases (patients with at least one preventable adverse event). Secondary outcome measures were inter-rater reliability of screening and identification, perceived workload, and face validity of results.
  
  
  RESULTS
  The prospective and retrospective methods identified similar numbers of medical and surgical cases (70% and 66% of the total, respectively) but the prospective method identified more preventable cases (64% and 40%, respectively), had good reliability for identification (kappa = 0.83), represented an acceptable workload, and had higher face validity. The cross sectional method showed a large number of false positives and identified none of the most serious adverse events. None of the methods was appropriate for obstetrics.
  
  
  CONCLUSIONS
  The prospective method of data collection may be more appropriate for epidemiological studies that aim to convince clinical teams that their errors contribute significantly to adverse events, to study organisational and human factors, and to assess the impact of risk reduction programmes.
authors.affiliation: Comité de Coordination de l'Evaluation Clinique et de la Qualité en Aquitaine, Hôpital Xavier Arnozan, 33604 Pessac, France. philippe.michel@ccecqa.asso.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Michel
authors.forename: Jean Luc
authors.initials: JL
authors.lastname: Quenon
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: de Sarasqueta
authors.forename: Olivier
authors.initials: O
authors.lastname: Scemama
mesh_terms: D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005602:France / Q000453:epidemiology; D016304:Hospitals, Private / Q000592:standards*; D006779:Hospitals, Public / Q000592:standards*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D019300:Medical Errors / Q000517:prevention & control* / Q000706:statistics & numerical data; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012308:Risk Management / Q000379:methods / Q000592:standards*; D012680:Sensitivity and Specificity