overestimation error =
= (percent given by diagnostician as the probability of a diagnosis) - (percent probability based on available evidence)
where:
• The ratio of the 2 values might also provide a measure of deviation.
• Ratio = (percent certainty given by the diagnostician) / (percent certainty based on available data)
Interpretation:
• A value near 0 indicates a current estimate of diagnostic probability.
• A large value indicates overestimation (overdiagnosis).
• A negative value indicates underestimation (underdiagnosis).
Consequences of overdiagnosis:
(1) unnecessary therapy
(2) unnecessary diagnostic tests
Reasons for overdiagnosis:
(1) placing more importance on a finding than justified
(2) failure to consider all evidence
(3) placing more emphasis on the consequences of failing to make the diagnose
