Subjectivity in decision making: common problems and limitations.

Subjectivity is an inescapable part of the diagnostic and decision making process. Limitations on memory are compensated for by invoking "diagnoses" as devices for managing information during diagnosis. Thus, large amounts of information can be stored as confirmations and departures from the diagnostic hypotheses. Well-documented limitations in probabilistic reasoning interfere with diagnosis and patient management. Uncommon diagnoses may be invoked inappropriately. Misconceptions of chance may lead to erroneous conclusions about health care. Most perplexing is that physicians attempting to incorporate patient preference in decision making are confronted with problems of subjective inconsistencies in patient valuation of outcomes of health care. The major problems of quantification and analysis are amenable to management through education, computing, and better patient data management. Problems of utility elicitation will require further research.