[EM] SODA arguments

Jameson Quinn jameson.quinn at gmail.com
Fri Feb 17 07:20:20 PST 2012

For those who feel that Bayesian Regret is the be-all-and-end-all measure
of voting system quality, that SODA's BR for 100% strategic voters will
beat all other systems, including Range/Approval.

For those who feel that Condorcet compliance is the be-all-and-end-all, a
majority Condorcet winner, or any Condorcet winner with 3 candidates and
full candidate preferences, is not just the winner with honest votes, but
in all cases the strategically-forced winner; this contrasts with Condorcet
systems, in which strategy can cause even majority- or 3-candidate- CWs to

For those who feel that strategic resistance is the most important, SODA is
unmatched. It meets FBC, solves the chicken dilemma, has no burial
incentive (ie, meets later-no-help), and even meets later-no-harm for the
two most-approved candidates (where it matters most). It's monotonic, and I
believe (haven't proven) that it meets consistency. It meets participation,
cloneproofness, and IIA for up to 4 candidates.

For those "middlebrows" who most value a system's acceptability to current
incumbents, SODA is top-of-the-line. It allows voters to vote
plurality-style and, if two parties are clearly favored by voters, allows
those two parties to prevent a weak centrist from winning, even if
polarization is so high that the centrist is an apparent Condorcet winner.

For those who want simplicity: while it's true that the SODA counting
process is more complicated than approval, the process of voting is
actually simpler than any other system, because you can just vote for your
favorite candidate. For the majority who agrees with their favorite
candidate's preferences, there is no strategic need to watch the polls and
figure out who the frontrunners are, and no nail-biting dilemma of whether
to rank others as equal to your favorite.

And for those who balk at delegation, SODA allows any voter to cast a
direct, undelegated ballot; and allows those voters who do delegate to know
how their vote will be used. Refusing to consider SODA because you don't
want to delegate, is like refusing to walk into a candy store because you
don't like chocolate; SODA allows, not requires, delegation.

I think pretty much everybody on this list falls into one or more of the
above categories. So, what's not to like about SODA?


ps. I clarified the SODA
the wiki, though there were no substantive changes. I improved the
formatting, marked the steps which are optional, and better explained that
winning candidates use their delegated votes first because precisely
because they will probably choose not to approve others.

Comments are welcome.
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