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Suppose for the sake of argument that on average women have higher rates of thinking something is physically wrong with them when there isn't. Is it not rationa

• Retric 8y ago
  Bayesian reasoning is a terrible fit for healthcare because it ignores risks. Suppose 99% of the time a set of symptoms is harmless and 1% of the time it's deadly. A 1% risk of death is extremely high and needs to be taken seriously even if ignoring it would be correct 99% of the time.
  • yasp 8y ago
    This exact case is discussed in Eliezer Yudkowsky's "An Intuitive Explanation of Bayes' Theorem" [0]. [0] http://yudkowsky.net/rational/bayes http://yudkowsky.net/rational/bayes
    • Retric 8y ago
      That's describing probabilities of truth, not the correct responses to those probables. I did not say false positives or false negatives etc, I simply said the post diagnosis odds. Doctors and patients have little reason to care about odds directly they care about Risk which is ~= odds * harm. Odds going from say 10 to 15% or 0.015% to 0.02% don't have big impacts on your net Risk.
      • yasp 8y ago
        Good point
  • tomp 8y ago
    That's exactly what Bayesian reasoning is. The other time I went to the doctor to complain about back pain, and get an appointment for a physio. The doctor asked me to do some movements that didn't seem directly related to my issues. Then she explained that they have to check for a specific condition (like a spinal bulge or something) that, albeit very rare, absolutely needs to be operated on as soon as possible.
    • deleted 8y ago
      [deleted]
• Dove 8y ago
  Rational, yes; fair, no. Group differences are real, and burying or ignoring that truth is doomed to failure, since it is obvious. However, we have a moral responsibility to evaluate every person as an individual - to give each the benefit of the doubt, regardless of how people who look like them tend to behave. I myself think this is a two way street. If you belong to a group with a particular characteristic and you're an exception, you may need to make an effort to make that explicit - with a statement, via behavior, via dress. And it is not evil when people make assumptions about you; it's understandable. At the same time, we should try to be fair to everyone, to keep in mind that exceptions exist to every rule, and to allow others to change our first perceptions of them easily. I think this approach walks the line between truth and justice, though I am certainly open to hearing a better strategy.
  • yasp 8y ago
    Unfortunately there is another dimension here which is that we're allocating a scarce resource (medical care). If one group has significantly higher rates of hypocondria (again, I don't know for sure whether this is true, but assume for argument's sake that it is), and we're forced to treat everyone as an individual (i.e. ignore this fact), then this necessarily deprives other groups of resources (medical care).
    • tehwebguy 8y ago
      I think the point is simply that if you walk in properly (appointment / insurance / etc) you should be properly diagnosed.
• dagw 8y ago
  Is it not rational for doctors to take a Bayesian approach and weight their diagnoses accordingly? Not without having very detailed information on exactly how big the difference is and, equally important, how these differences are distributed within each sub-population.
  • yasp 8y ago
    So Bayesianism is good but only sometimes?
    • dagw 8y ago
      Bayesian reasoning is good when applied rigorously, but can be dangerous when applied sloppily and lazily, since people are terrible at subjectively estimating probabilities and tend to be way over optimistic when updating their priors with any new information they receive. Basically people will treat information that should realistically cause them to update their priors from 50-50 to 51-49 as if it was information that should cause them to update to 80-20 (and then they round off too 100-0).