When all Possible Diagnoses are Rare and Doctors’ Predictions Differ Widely

“An infection of that size of that bacteria in that part of the lungs is very unlikely. It’s probably a fungal infection.” “A fungal infection producing so few symptoms is very unlikely. It’s probably cancer.” “Cancer after negative biopsies in two different places is very unlikely. It’s probably all due to the bacterial infection.” “Negative biopsies are a dime a dozen. Cancer is still a real possibility.”

Doctors’ predictions were all over the map during my husband’s recent medical episode. So were their reactions to new test results. Intellectually I understood why: once all the remaining logical possibilities were rare, most of their clinical experience didn’t help in assessing probabilities. At the time, the diverging probabilities and their explanation provided health-economist-me and my biostatistician-husband with a bit of distraction from our emotions. Now that things look virtually certain to be fine, I see some lessons for patients, their families and physicians. Continue reading