title: Uncovering bias in the cytologic evaluation of cervical squamous lesions.
abstract: OBJECTIVE
  It is well recognized that biases exist in medical decision making. We sought evidence for such bias in diagnostic testing.
  
  
  METHODS
  We investigated whether a cytotechnologist's Papanicolaou (Pap) test interpretation of a squamous cell abnormality influenced the likelihood of making the same interpretation again that day using analysis based on the β distribution.
  
  
  RESULTS
  For squamous intraepithelial lesion (SIL) interpretations, significant deviation away from the mean daily diagnostic rate was seen within all three cytotechnologists and, for atypical squamous cells of undetermined significance interpretations, within two of three.
  
  
  CONCLUSIONS
  Cytotechnologists are not influenced by an expected number of abnormal Pap cases per day since this would result in deviation toward the mean daily rate of diagnosis. Possible explanations for the unanticipated clustering of SIL interpretations include clinical clustering effects or, alternatively, the influence a SIL interpretation might have on lowering the threshold for this interpretation again in subsequent specimens on the same day. The analysis presented here could serve as a model to detect bias in other aspects of medical decision making.
authors.affiliation: From the Divison of Dermatopathology and.
authors.forename: Allison R
authors.initials: AR
authors.lastname: Larson
authors.affiliation: Division of Cytopathology, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
authors.forename: Edmund S
authors.initials: ES
authors.lastname: Cibas
authors.affiliation: From the Divison of Dermatopathology and.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Granter
authors.affiliation: From the Divison of Dermatopathology and alaga@partners.org.
authors.forename: Alvaro C
authors.initials: AC
authors.lastname: Laga
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D005260:Female; D006801:Humans; D065006:Papanicolaou Test; D030361:Papillomavirus Infections / Q000175:diagnosis; D011336:Probability; D015203:Reproducibility of Results; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis*; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis*
keywords: Bias; Cytology; Pap; Pathology; β distribution