In part I of this series I discussed clinical pathways – how clinicians approach problems and the role of diagnosis in this approach. In part II I discussed the thought processes involved in deciding which diagnostic tests are worth ordering.
In this post I will discuss some of the logical fallacies and heuristics that tend to bias and distort clinical reasoning. Many of these cognitive pitfalls apply to patients as well as clinicians.
Pattern recognition and data mining
Science, including the particular manifestation we like to call science-based medicine, is about using objective methods to determine which patterns in the world are really real, vs. those that just seem to be real. The dire need for scientific methodology partly results from the fact that humans have an overwhelming tendency to automatically sift through large amounts of data looking for patterns, and we are very good at detecting patterns, even those that are just random fluctuations in that data.