71–80 of 93 posts
The criteria considered by the theorem concern how democratic a voting system is. I'd argue that 'democraticness' is secondary to two other criteria: accountability and government-effectiveness. Accountability means that bad rulers can get voted out of office when enough people are displeased. Government-effectiveness means that the resulting government can practice good governance. When considering these criteria, I…
Few theorems in economics, or political science in this case, are as disappointing as this one. Another one is Sonnenschein-Mantel-Debreu. https://en.wikipedia.org/wiki/Sonnenschein%E2%80%93Mantel%E2... SMD: rational individuals do not sum up to a rational aggregate.
Can I get a simple wikipedia explanation? That was the most challenging wikipedia article I've ever read.
There is a simple explanation in the introduction: In short, the theorem states that no rank-order voting system can be designed that always satisfies these three "fairness" criteria: 1. If every voter prefers alternative X over alternative Y, then the group prefers X over Y. 2. If every voter's preference between X and Y remains unchanged, then the group's preference between X and Y will also remain unchanged (even…
An amusing anecdote which illustrates why independence of irrelevant alternatives is desirable: After finishing dinner, Sidney Morgenbesser decides to order dessert. The waitress tells him he has two choices: apple pie and blueberry pie. Sidney orders the apple pie. After a few minutes the waitress returns and says that they also have cherry pie at which point Morgenbesser says "In that case I'll have the blueberry p…
What is IIA? Can't find anything relevant on Google.
An amusing anecdote which illustrates why independence of irrelevant alternatives is desirable: After finishing dinner, Sidney Morgenbesser decides to order dessert. The waitress tells him he has two choices: apple pie and blueberry pie. Sidney orders the apple pie. After a few minutes the waitress returns and says that they also have cherry pie at which point Morgenbesser says "In that case I'll have the blueberry p…
This is a comment directed to the various replies... What is IIA? Can't find anything relevant on Google.
Earlier quoted context omitted.
In short: For a voting system (ranking of some candidates based on preferences of voters), it would be nice if: - A single voter cannot determine the ranking (as a dictator) - For every possible set of voter preferences, there is an outcome (not random) - If everyone likes candidate A over candidate B, then in the final ranking candidate A should be ranked higher than candidate B - If one prefers A over B when compar…
Are the counterexamples offered by the theorem pathological, in the sense that they are unlikely to occur in practice but are theoretically possible? Or would they arise in practice frequently using standard rank voting systems?
Can I get a simple wikipedia explanation? That was the most challenging wikipedia article I've ever read.
This is how I was taught it (or understood I was taught it) - at law school, so it might have been dumbed down. The impossibility is the impossibility of ensuring rational (transitive) outcomes amongst ranked preferences and adhering to a set of fair and democratic norms. A rational transitive outcomes is one in which votes result in option A being preferred over option B and option B being preferred over option C, s…
Earlier quoted context omitted.
In the context of voting, all IIA represents is the requirement that we only take into account the information on the ballots..
I don't see this. Could you elaborate?
An amusing anecdote which illustrates why independence of irrelevant alternatives is desirable: After finishing dinner, Sidney Morgenbesser decides to order dessert. The waitress tells him he has two choices: apple pie and blueberry pie. Sidney orders the apple pie. After a few minutes the waitress returns and says that they also have cherry pie at which point Morgenbesser says "In that case I'll have the blueberry p…