The psychological effect resulting from the reduction of probability, from certain to probable, that occurs when we give less significance to outcomes that are more certain than their probability justifies. This occurs becuase we are irrationally attracted to certainty. In other words, people are more concerned about a reduction in probability from 100% to 95%, for a positive event, than a 5% decrease in probability justifies. Similarly, we are much more concerned about an increase in risk of 0% to 2%, for a negative event, than we should be (Kahneman, 311-313).
Certainty Effect
