Suppose there are three individuals in society trying to rank three social states \((A, B,\) and C). For each of the methods of social choice indicated, develop an example to show how (at least) one of the Arrow axioms will be violated. a. Majority rule without vote trading. b. Majority rule with vote trading. c. Point voting where each voter can give \(1,2,\) or 3 points to each alternative and the al ternative with the highest point total is selected.

Short Answer

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Question: Give an example that demonstrates each of the following social choice methods failing to satisfy one of Arrow's axioms: (a) Majority rule without vote trading, (b) Majority rule with vote trading, and (c) Point voting. Answer: (a) Majority rule without vote trading violates the Independence of Irrelevant Alternatives axiom, as shown in the scenario where removal of alternative C changes the ranking between A and B. (b) Majority rule with vote trading also violates the Independence of Irrelevant Alternatives axiom, as the same scenario from example a applies even with vote trading. (c) Point voting, with individuals allocating 1, 2, or 3 points per alternative, violates the Independence of Irrelevant Alternatives axiom when the removal of alternative B changes the ranking between alternatives A and C.

Step by step solution

01

Example a: Majority rule without vote trading

Consider these preferences for three individuals: Individual 1: A > B > C Individual 2: B > A > C Individual 3: B > C > A Using majority rule without vote trading, preferences are as follows: - A vs B: B wins (2-1) - B vs C: B wins (2-1) - C vs A: A wins (2-1) The alternative with the most wins is B, but in this scenario, the Independence of Irrelevant Alternatives axiom is violated. If we were to remove alternative C, the preferences would be: Individual 1: A > B Individual 2: B > A Individual 3: B > A B still wins (2-1), but the ranking between A and B has shifted.
02

Example b: Majority rule with vote trading

Consider these preferences for three individuals: Individual 1: A > B > C Individual 2: B > A > C Individual 3: C > B > A Suppose Individual 3 trades their vote with Individual 2, for B as the winner. This would result in: Individual 1: A > B > C Individual 2: B > A > C Individual 3: B > C > A Using majority rule with vote trading, the same results occur as in Example a, violating the Independence of Irrelevant Alternatives axiom.
03

Example c: Point voting (1, 2, or 3 points per alternative)

Consider these preferences and point allocations for three individuals: Individual 1: A (3 points) > B (2 points) > C (1 point) Individual 2: B (3 points) > A (2 points) > C (1 point) Individual 3: B (3 points) > C (2 points) > A (1 point) The total points for each alternative: A: 3+2+1 = 6 points B: 2+3+3 = 8 points C: 1+1+2 = 4 points Alternative B is selected as it has the most points. However, if alternative B is removed, the scenario will now look like this: Individual 1: A (2 points) > C (1 point) Individual 2: A (2 points) > C (1 point) Individual 3: C (2 points) > A (1 point) The total points for A and C with B removed: A: 2+2+1 = 5 points C: 1+1+2 = 4 points Alternative A is selected, but the ranking between A and C shifted. Thus, this method violates the Independence of Irrelevant Alternatives axiom.

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Most popular questions from this chapter

The demand for gummy bears is given by \\[ g=200-100 P \\] and these confections can be produced at a constant marginal cost of \(\$ .50\) a. How much will Sweettooth, Inc., be willing to pay in bribes to obtain a monopoly con cession from the government for gummy bear production? b. Do the bribes represent a welfare cost from rent seeking? c. What is the welfare cost of this rent-seeking activity?

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