An important part of decision making in many contexts is the estimation of numerical values for uncertain quantities, such as the projected costs of a development project or the number of people who use illegal drugs. In previous research, estimation accuracy for such quantities was found to be...

Four groups of college students were each given two base-rate problems. Three of the groups were given an aid with the first problem: (a) An instruction to list factors or aspects that were relevant to solving the problem, (b) a fill-in-the-blank algorithm that provided the correct solution, or...