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Majority score voting: Difference between revisions
→Other scenarios explored
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Note that A, the bigger of the two subfactions, must necessarily be above the 50-point threshold in step 2, so Z will be safely eliminated. In many cases, B, the smaller subfaction, will fall short of 50 points. This helps explain the rationale for putting that threshold at 50 points.
This is not to say that majority score solves the chicken dilemma 100%. It is still possible for the smaller subfaction B to win if they largely reject the A while the A voters largely accept B. And if both factions largely reject, Z can win. But the key word there is "largely"; unlike the case with [[approval voting]] or [[score voting]], this strategy will not work if it's done by only a few individual voters, but only if one subfaction uses it significantly more often than the other. Given that organizing such a coordinated betrayal in secret would be hard, and that doing so openly would invite mutually-destructive retaliation, it seems that majority score voting has a good chance of avoiding this problem.
As a final tricky scenario, consider what happens in the above case if the minority Z prefers the smaller subfaction B. That results in a [[center squeeze]] scenario: one where candidate B is a [[Condorcet winner]] (able to beat either rival in a one-on-one race) but an honest plurality loser (with the smallest faction of direct supporters). This is more common than one might think; candidate B is fighting an ideological battle on two fronts, while candidates A and C are free to triangulate towards the middle without losing supporters, so the fact that B has the smallest direct support may not reflect a lack of quality. Thus, generally speaking, as long as each faction considers their second choice to be more than half as good as their first choice (taking the worst choice as 0), it's pretty clear that the Condorcet-winner candidate B is the one who democratically "should" win this election.
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One interesting aspect in the above three scenarios: "assist" is only strategically favored in the case of a center squeeze scenario, when the A and C voters are helping B, whom they see as the the "lesser evil", beat the other extreme. If there isn't a center squeeze, voters need only use "support", "accept", or "reject". In fact, even in center squeeze, voters could get by without "assist", as long as enough A and C voters were willing to support B outright. So eliminating the "assist" option would not substantially change the strategic outcome; but it would reduce the expressive power available to the A and C voters in a center squeeze scenario. Thus majority score sacrifices some possible extra simplicity in return for this increased expressive power.
It is very rare to have a voting system which can deal with both chicken dilemma and center squeeze. The two situations are very similar, even when voted honestly, and yet the "correct" outcome is different. And under strategic voting in many voting systems, it is very easy for the two different scenarios to lead to identical ballots. Delegated voting systems such as [[SODA voting]] can deal with both; but without that kind of explicit participation in the voting process from the candidates, it is very hard to find a system which deals with both types of scenario better than majority score does.
== As the first round of a two-round system ("majority score with runoff") ==
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