Communicating Risks

Mike has written several posts on risk perception. What does it mean when we say that a patient has a 3% chance of having an MRSA infection?  How do you communicate that risk to patients or other HCW or even hospital administration?  One aspect of decision science deals with communicating risk; there were several sessions on the topic when I last attended the annual SMDM meeting.

There is a recent post that covers the topic well in Decision Science News, edited by Dan Goldstein from Yahoo! Research and the London Business School. Try to answer the question below.  The answer is available if you expand the post (and if you read the DSN post)

The probability of colorectal cancer in a certain population is 0.3% [base rate]. If a person has colorectal cancer, the probability that the haemoccult test is positive is 50% [sensitivity]. If a person does not have colorectal cancer, the probability that he still tests positive is 3% [false-positive rate]. What is the probability that a person from the population who tests positive actually has colorectal cancer?

ANSWER: 5% (Don't feel badly if you guessed incorrectly as most physicians guess 50% or 47%) However, if we can't understand risks ourselves, how can we communicate them to patients?



Link: Decision Science News Post (Some Ideas on Communicating Risk to the General Public)