Arrow’s Impossibility Theorem

Definition

Arrow's Impossibility Theorem states that no rank-order voting system can meet all of a specified set of criteria for fairness. It proves the inherent limitations and trade-offs in collective decision-making processes.

5 Must Know Facts For Your Next Test

1. Proposed by economist Kenneth Arrow in 1951.
2. The theorem applies to any voting method that ranks preferences.
3. It specifies three fairness criteria: non-dictatorship, unrestricted domain, and independence of irrelevant alternatives.
4. Arrow's Theorem demonstrates the impossibility of creating a perfect voting system that satisfies all three criteria simultaneously.
5. This theorem is also known as the General Impossibility Theorem.

Review Questions

• What are the three fairness criteria outlined in Arrow's Impossibility Theorem?
• Who proposed Arrow's Impossibility Theorem and in what year?
• Why does Arrow's Impossibility Theorem suggest about creating an ideal voting system?

Related terms

Non-Dictatorship: A condition where no single voter possesses the power to always determine the group's preference.

Unrestricted Domain: A criterion stating that every possible order of preferences should be allowed among voters.

Independence of Irrelevant Alternatives: A principle stating that if a preference ranking between two options changes, it should only be influenced by those two options and not by changes in other irrelevant alternatives.