Which one of the following is NOT a rule for estimating the likelihood of outcomes of any decision?

The correct answer is A. Assessing utility is not a heuristic for estimating the likelihood of outcomes. It concerns how much value a decision-maker attaches to an outcome.

The question points to the heuristics identified by Tversky and Kahneman in their work on judgement under uncertainty. People often judge probability through mental shortcuts rather than strict calculation:

• Representativeness (B): probability is judged by how closely an event resembles a stereotype or prototype, which leads to neglect of base rates.
• Availability (C): events that come to mind easily are judged more likely, so vivid news of a rare event inflates its perceived risk.
• Adjustment (D): the anchoring-and-adjustment heuristic starts from an initial figure and shifts insufficiently, so estimates stay close to the anchor.

Assessing utility belongs to decision theory, where expected utility multiplies the probability of an outcome by its value. Probability and utility are separate inputs, and the heuristics above concern only the first.

This links to behavioural economics and to Mains questions on policy under uncertainty, such as disaster preparedness, where officials often overreact to recent, vivid events.

Trap: aspirants see "utility" in a decision context and assume it must be part of likelihood estimation, forgetting that it measures desirability, not probability.