The weighing of pathological and non-pathological information in clinical judgment

Acta Psychol (Amst). 2000 Mar;104(1):87-101. doi: 10.1016/s0001-6918(99)00055-4.


On the basis of the classic data of Meehl (1959), I examine how clinical psychologists use the MMPI scales to judge the degree of pathology of psychiatric patients by comparing linear models of the judgment to a linear model of the criterion (the actual diagnosis of the patients). This comparison reveals that excessively heavy weight is assigned to pathological information in comparison to non-pathological information. Additional analyses reveal that this biased weighing also influences the actual diagnosis and that it is a major determinant of the accuracy of clinical judgment. It is suggested that these effects arise from a confirmation bias associated with the hypothesis that a patient has severe, rather than mild, pathology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Clinical Competence / standards*
  • Decision Making*
  • Diagnosis*
  • Humans
  • Linear Models
  • Observer Variation*
  • Psychology / standards*