There is an interesting article in the NY Times on how the CDC and other health agencies will try to deal with public perceptions that H1N1/Swine Flu vaccine may have been the cause of certain medical conditions after a person has received the vaccine. See: http://www.nytimes.com/2009/09/28/health/policy/28vaccine.html?_r=1&th&emc=th
It seems to me that two key factors are being used: (1) Information about the baserate of medical conditions in general (i.e., how often should we expect something like a miscarriage to occur). (2) Emphasizing that the conditional probability the development of a medical condition (such as a miscarriage) after getting vaccine is the same as the conditional probability of developing the medical condition after not getting the vaccine. That is, Prob(miscarriage|vaccine shot) = Prob(miscarriage|no vaccine shot) Technically, I think, there should be a group of women who receive a placebo vaccine instead of the population baserate of women having a miscarriage which I believe that the CDC will use [i.e., Prob(miscarriages)]. The problem of dealing with people's illusory perception of correlation and causation is a hard one though a significant amount of research has been done on this topic. Lance Rips has written a review of this area that some might find interesting (it is a chapter from Adler & Rips' [eds.] book "Reasoning"); see: http://mental.psych.northwestern.edu/publications/causality_v15.pdf -Mike Palij New York University m...@nyu.edu --- To make changes to your subscription contact: Bill Southerly (bsouthe...@frostburg.edu)
