First Advisor

Barry F. Anderson

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Psychology






Diagnosis, Diagnostic errors



Physical Description

1 online resource (69 p.)


This study examined the effects of sensitivity, specificity and result of diagnostic tests on the uses which physicians make of those results. These were compared with the Bayesian model of probability adjustment, which is generally accepted for medical diagnosis. Ninety six active members of the Oregon Academy of Family Physicians were interviewed by telephone, using a case scenario describing a patient with a newly discovered breast lump. Subjects estimated prior probability of malignancy, based on history and physical findings, and then estimated posterior probability following results of a mammogram. Mammograms varied by result (positive or negative) and by high and low values for sensitivity and specificity. Subjects were asked to indicate their confidence in each probability estimate. About one third of the subjects were also asked for their treatment threshold -- that point at which they would change from a policy of watchful waiting to one of taking some action, which was usually biopsy of the lesion.


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