@toby-pereira said in score voting is king, condorcet not so much:

It's been said that score suffers worse with one-sided strategy than other methods. That is - if the supporters of one candidate strategise more than the supporters of another, then the result will be more skewed (favour the strategisers) under score than some other methods. Would you agree with that, and do you see it as a problem?

I ran it on a spatial bimodal electorate with a realistic (half-random) viability signal, average strategy pinned at 90%, comparing symmetric (90% of each faction strategizes) against the most lopsided split possible at that level (100% of one faction, 80% of the other).

method 90/90 symmetric 100/80 asymmetric change Score (0–5) 0.943 0.933 −0.010 Approval 0.926 0.921 −0.005 STAR 0.914 0.905 −0.009 Ranked Pairs 0.874 0.859 −0.016 Schulze 0.863 0.840 −0.022

So at a fixed strategy level, adding maximum asymmetry costs Score about a point, and costs the Condorcet methods more, Ranked Pairs −0.016, Schulze −0.022. Approval is the most robust of all. The ordering of who's hurt is the reverse of the claim: one-sided strategy is harder on the ranked methods here than on the cardinal ones.

I'd agree the underlying property is real, score does respond to one-sided exaggeration. But two things keep it from being a problem in practice. The optimal score strategy is just threshold voting (approve/max everyone above your expected value of the winner), which is close to a sincere ballot, so the distortion per unit of asymmetry is small. And every method has an asymmetric-strategy weakness; the ranked methods' version is burial, which diverges much further from sincerity and does more damage, which is what the table shows.

The first two voters fail to use the endpoints of the range available to them. Do you expect such behavior in political elections that matter? I think comparisons of voting systems based on hypothetical examples should begin with the voters' valuations of the possibilities normalized. I don't know that it's worth studying examples where voters voluntarily give up power. We as students of these systems need all the time and attention we can put on cases where the purpose of the election is to resolve strong political disagreement among the voters. We need elections to work well when the voters are struggling for political power. Such voters would use the endpoints of the range unless they are not properly informed as to how the system works.