Do Decision Biases Predict Bad Decisions? Omission Bias, Naturalness Bias, and Influenza Vaccination

Many medical outcomes depend on choicesmade by patients. From deciding whether or not to exercise, go on a diet, or obtain a flu vaccine, patients make numerous health decisions. Unfortu-nately, as with any decision, people do not always decide in a normatively rational manner. A large body of research has identified decision biases or deviations from normative theory (for reviews, see Gilovich and others1 and Kahneman and others2). Traditionally, these decision biases have been demonstrated through hypothetical scenarios or laboratory tasks.3 It remains unclear the extent to which exhibiting decision biases in a hypothetical scenario is indicative of making poor decisions in real life. Although some studies have examined the relationship between individual difference vari