Arrow's impossibility theorem: Difference between revisions
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(The loopholes in Arrow's theorem were closed by Gibbard. See my comment on the Talk page.) |
Dr. Edmonds (talk | contribs) (→Systems which claim to evade Arrow's Criteria: Saying that all systems have some bad feature is not specific enough. It is about strategic voting.) |
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==Systems which claim to evade Arrow's Criteria== |
==Systems which claim to evade Arrow's Criteria== |
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Some activists believe that Arrow's theorem only applies to [[Ordinal Voting|ordinal voting]] and not [[cardinal voting]]. They point out that that it is technically possible for several cardinal systems to pass all three fairness criteria. The typical example is [[score voting]] but there are also several [[Multi-Member System |multi-winner systems]] which proport to pass all three of Arrow's original criteria. |
Some activists believe that Arrow's theorem only applies to [[Ordinal Voting|ordinal voting]] and not [[cardinal voting]]. They point out that that it is technically possible for several cardinal systems to pass all three fairness criteria. The typical example is [[score voting]] but there are also several [[Multi-Member System |multi-winner systems]] which proport to pass all three of Arrow's original criteria. Additionally, there are cardinal systems which do not pass all criteria but this is not due to Arrow's theorem; for example [[Ebert's Method]] fails [[Monotonicity]]. |
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| ⚫ | However, subsequent social choice theorists have expanded on Arrow's central insight, and applied his ideas more broadly. For example, the [[Gibbard-Satterthwaite theorem]] (published in 1973) holds that any deterministic process of collective decision making with multiple options will have some level of [[strategic voting]]. As a result of this much of the work of social choice theorists is to find out what types of [[strategic voting]] a system is susceptible to and the level of susceptibility for each. For example [[Single Member system | Single Member systems]] are not susceptible to [[Free riding]]. |
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| ⚫ | However, subsequent social choice theorists have expanded on Arrow's central insight, and applied his ideas more broadly. For example, [[ |
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==See also== |
==See also== |
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*[[Gibbard-Satterthwaite theorem]] |
*[[Gibbard-Satterthwaite theorem]] |
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