Äänestysparadoksi

Äänestysparadoksi, also known as the voting paradox, is a concept in social choice theory that describes a situation where collective preferences can lead to cyclical outcomes, making it impossible to determine a stable winner. This phenomenon arises when a group of voters has three or more options, and their individual preferences, when aggregated, do not produce a clear, consistent ranking of all options. Instead, the collective preference might suggest that option A is preferred to option B, option B is preferred to option C, and yet option C is preferred to option A. This creates a paradox because no single option can be deemed the overall best choice for the group.

The voting paradox is often illustrated with a simple majority voting scenario. For example, consider three voters and three candidates: A, B, and C. Voter 1 prefers A over B and B over C. Voter 2 prefers B over C and C over A. Voter 3 prefers C over A and A over B. When comparing pairs, A beats B by a vote of 2 to 1 (Voters 1 and 3). B beats C by a vote of 2 to 1 (Voters 1 and 2). However, C beats A by a vote of 2 to 1 (Voters 2 and 3). This creates a cycle: A > B > C > A, where the "greater than" symbol signifies collective preference.

This paradox highlights the challenges in aggregating individual preferences into a coherent group decision. It demonstrates that even with rational individual voters, the outcome of a democratic process can be inconsistent and paradoxical. The voting paradox has significant implications for the design of electoral systems and decision-making processes, suggesting that simple majority rule may not always lead to fair or stable results, especially when there are multiple alternatives.