SODA voting (Simple Optionally-Delegated Approval): Difference between revisions
SODA voting (Simple Optionally-Delegated Approval) (view source)
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'''Vote for as many candidates as you approve, or vote for one candidate to delegate your vote:'''<br>
'''If you only vote for one candidate, your vote is delegated to that candidate, unless you check the box below.''' A delegated vote means that, if your favorite candidate shows preferences above, he or she may use your vote to approve of one or more of the most-preferred of them. For instance, if he or she can not win, he or she might approve of some other "compromise" candidate(s) who can.<br>
▢ Do not delegate. Do not let the candidate I voted for add approvals to my vote.
''Note: If you vote for more than one candidate, or if you vote for a write-in or other candidate with no declared preferences, your vote is not delegated. In that case, no-one can add approvals to your vote, and it does not matter whether you check the box above.''
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=== Full, step-by-step rules ===
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:a) '''Before the election, all candidates must strictly rank
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:b) ''(optional)'' Candidates may <u>enforce any prior agreements</u> of mutual preferences by changing their own preferences in response to those of others*. ''This enforcement mechanism is designed to deter betrayals, so that it should almost never actually need to be used. Candidates, realizing that changing preferences at this point will only make them look untrustworthy, will prefer agree on mutual approvals beforehand.''
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<big>2. Voters vote delegated plurality-style votes or non-delegated approval-style votes</big>
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<small><u>'''Enforcing mutual approval agreements'''</u>: If A ranked B higher than B ranked A, then A may respond by lowering B's ranking. B may respond by raising A, and A may then respond by restoring B to the original ranking. If B raised A above C, then C may lower A, but A may not respond. Three rounds of response are all that are allowed. </small>
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:a) ''(optional)'' Ballots list all candidates in order from candidates who submit the <u>most complete</u> rankings of other candidates, to those who submit the least. Where this is a tie, ordering is random. ''This is a slight incentive for candidates to submit a complete ranking in order to appear high on the ballot.''
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<small><u>'''Most complete'''</u>: Completeness of ranking is scored by how many possible pairs of other candidates contain two candidates at different levels.</small>
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:b) '''Voters may approve one or more candidates, and also have the option to mark "Do not delegate". <u>Delegated votes
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<big>3. Candidates take turns to publicly use their delegated votes, in descending order of delegated votes.</big>
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:a) ''(optional)'' There is a one-week period for candidates to analyze and negotiate based on these preliminary results. ''Actually, the optimal strategies for all candidates and the resulting winner will already be obvious. Usually, all candidates except this winner would concede as soon as preliminary results are announced. However, for the occasional candidate inclined to act irrationally in a way that matters - say, by not delegating to an ally, even though the alternative is to see an enemy elected - this interim period would give them a chance to rethink things and come into reason.''
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<small><u>'''Delegated votes'''</u>:The delegated votes for candidate X is the number of ballots that approve only X and do not mark "Do not delegate". X will get a chance to effectively add additional approvals to these votes; or, if X has less than 5% approval, then additional approvals will be added automatically, in order to attain a better result by X's predeclared preferences.
<u>'''Total approvals'''</u>:The total approvals for candidate X is initially the number of ballots that approve X, including X's delegated ballots. This number increases through the process as other candidates use their delegated ballots to approve X.</small>
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:b) '''Each candidate, in descending order of number of delegated votes, may <u>use some or all of their delegated ballots</u> to approve zero or more other candidates, consistent with their predeclared preferences. That is, they may add a number up to their delegated vote tally to the other candidates' approval tallies, as long as they do not give more to a less-preferred candidate.''' ''If, considering the votes, a candidate can win, they will probably prefer not to approve other candidates. If there are two allied candidates who need to cooperate to win, the one with more approvals has first chance not to approve the other. That way, when it's the weaker candidate's turn, they will no longer have the possibility of winning, so the weaker will approve the stronger.''
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<small><u>'''Use their delegated ballots'''</u>: The process by which a candidate effectively adds approvals to the votes delegated to him or her. When, for example, candidate A uses their delegated ballots to approve of B and C, then B and C's approval totals are each increased by A's delegated vote total. When it is a candidate's turn, they may choose to approve of nobody else, for instance if they believe they will win; but this counts as using their delegated votes, and they will not be given another chance to change that decision. When all candidates have used their votes, the election is over.</small>
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::i. If the candidate using their delegated votes has more than 5% approval, '''they may choose which candidates approve on their delegated ballots, <u>consistent with preferences</u>.'''
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<small>'''<u>Consistent with preferences</u>'': For example, candidate A may not approve B and not C unless A predeclared a preference for B over C.</small>
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::iii. ''(optional)'' If the candidate is a write-in or got less than 1% direct approvals from voters, they may not use their delegated votes. However, any candidate may approve a write-in, regardless of the predeclared preferences. ''Write-ins do not have a chance to declare or figure in the pre-declared preferences. Candidates with less than 1% are not allowed to use delegated votes to discourage a frivolous proliferation of candidates.''
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<small>'''<u>Automatic approvals</u>''': When approvals are assigned automatically for candidate X, they are set to approve as many of their pre-declared preferences as possible without approving both of the two candidates with the highest current approval totals that they prefer differently. (For example, say that X's preferences were for A>B>C>D>E, and the approval totals are 10, 30, 10, 20, and 15 alphabetically. B and D have the highest totals. So X's delegated ballots will be assigned to approve as many candidates as possible without approving both B and D; that is, they will approve A, B, and C.)</small>
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<big>4. When step 3b ends, highest total wins</big>
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=== Notes on rules ===
(technical issues; moved to talk page)
== Example ==
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{{Tenn_voting_example}}
In this simplified example, all the residents of each city agree on the rankings of all the other cities, so there would be no reason for anybody to do anything but bullet vote. Memphis has the first option to choose approvals for its delegated votes, and, as the leader, decides to approve noone but itself. Nashville goes second; it is the pairwise champion (Condorcet winner), so it also declines to approve any others.
== Advantages ==
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# SODA should be generally '''acceptable to honest officeholders''', who are winners in a Plurality two-party system. Most of their familiar ways of thinking about the campaign would still work - except that it would reduce negative campaigning. Plurality-style voting still works just fine, and if most votes are for major parties, this system will cleanly allow a major party to win, in many cases without going to the delegation round (especially if the major-party candidates do not pre-announce delegation preferences, thus preventing an extorting minor party from demanding their delegated votes).
# SODA would make a politician's job '''more fun'''. Less time spent on fundraising (see process advantage #3), fewer attack ads from opponents (see process advantage #2); what's not to like? Sure, nobody would be a politician today without a high tolerance for these problems, but even for politicians, negative ads and the fundraising treadmill have gotten out of hand.
# SODA '''reduces the threat from unserious candidates'''. Under plurality,
== Criticism and responses ==
=== "
While the rules for counting SODA are indeed a bit complex, no other system is simpler for the voters, allowing them to simply vote their favorite and go home confident that their vote has full strategic power.
=== "Delegation is undemocratic"? No; it's a free choice by voters. ===
Simple response: if you don't want to delegate, don't delegate. You can still vote for whomever you want.
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Simple response to a ''politician'' who makes this argument: "You just want the only smoke-filled room to be the one inside your skull." That is, minority factions '''should''' have a seat at the table, as long as everything is done transparently. The two-party system stifles some of the valid concerns of the members of the party coalitions. In SODA, all vote totals, preference orders, and final approvals added to delegated ballots are known; in the end, that's not a smoke-filled room, it's a transparent seat at the table, with a just degree of power which is derived from the people.
=== "There are other systems which are better in some ways"? Yes, but unlike them, SODA is better than plurality in ALL ways. ===
This is true. [[Condorcet]], [[Range Voting]], and Median systems like [[Majority Approval Voting]] (or others: [[Majority Judgment]], [[MCA]], or [[Bucklin]]) each have some claim to be the "best voting system". But SODA is the best system which has no downsides versus plurality. All those other systems require more-complicated ballots. All of them require more-complicated, or even dishonest, strategic decisions from the voter, to get the most effective vote.
So in the end, while any of those other systems would be, in my opinion, a clear net benefit versus plurality, with SODA you don't need any qualifications like "'''net''' benefit" or "in my opinion". It is simply better, in every way.
=== "Sounds too much like a parliamentary system, which has caused problems in [Italy / Israel / wherever]"? No, SODA still leaves "buck stops here" responsibility. ===
SODA does involve some parliamentary-style negotiation for a short period after each election. But then it's done, and the winner is in power until the next election. Unstable parliamentary countries, or ones where minority parties have inordinate power, are that way because minority parties can leave the governing coalition at will, triggering new elections. SODA does not have that problem; in many ways, it's really the best of both worlds between a 3-branch system and a parliamentary system.
=== "Why go to the trouble of pre-announced rankings and a second round? Why not just have candidates pre-announce the approvals they will add to their delegated votes?" Because the best compromise is only clear after the votes are tallied. ===
This sounds appealing, but would not work if two similar candidates were in a close race to see which had more first-choice votes, while an opponent stood ready to take advantage if they split the vote (that is, in the Chicken Dilemma, also discussed on the talk page). The system as it stands allows the similar candidates to see, after the votes are counted, which of them deserves to win: the one with the higher approval total. That one will go first and not delegate their votes, and then other one (of necessity) will.
In general, this system, because it provides perfect information on voting totals at the time when delegation is happening, will make strategy obvious. This has the paradoxical result that, as long as most voters agree with their favored candidate's chosen ranking order, this system will in practice be '''more Condorcet compliant than a Condorcet method''' (because strategy could confound a true Condorcet method more often than SODA).
== Criteria Compliance ==
SODA itself does not satisfy [[monotonicity]] due to a complicated and implausible scenario involving 5 or more candidates. However, a slightly-modified version in which, before the delegated assignments, candidates can self-assign a penalty to be assessed at the end of the delegated assignment round, does. This modified version, MODA, is effectively identical to SODA for any plausible real-world election.
It does not satisfy the [[independence of irrelevant alternatives]] criterion in general, but it does if the "irrelevant alternative" is assumed to delegate votes in the same way as any candidate whose delegable votes they supplant. Similarly, it can only pass the [[participation]] and [[consistency]] criteria if it is assumed that candidate delegations do not change. These assumptions are ''not'' realistic, but they do show that the method is in some sense "close to" passing these criteria.
In any case where honest delegation could show a majority Condorcet winner, such delegation forms a strong Nash equilibrium. This shows that in general, strategic refusal to delegate is likely to fail.
=== Condorcet criterion (includes highly technical discussion) ===
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*''Candidates are honest'' in their pre-election rankings. This could be because they are innately unwilling to be dishonest, because they are unable to calculate a useful dishonest strategy, or, most likely, because they fear dishonesty would lose them delegated votes. That is, voters who disagreed with the dishonest rankings might vote approval-style instead of delegating, and voters who perceived the rankings as dishonest might thereby value the candidate less.
*''Candidates are rationally strategic'' in sharing their delegated vote. Since this process is sequential, game theory states that there is always a subgame-perfect Nash equilibrium, which is always unique except in some cases of tied preferences.
*''Voters'' are rationally strategic or otherwise able to use the system to ''express all relevant preferences''. That is to say, all voters fall into one of two groups: those who agree with their favored candidate's declared preference order and thus can fully express that by delegating their vote; or those who disagree with their favored candidate's preferences, but are aware of who the Condorcet winner is, and are able to use the approval-style ballot to express their preference between the CW and all second-place candidates. "Second place" means the Smith set if the Condorcet winner were removed from the election; thus, for this assumption to hold, each voter must prefer the CW to all members of this second-place Smith set or vice versa. That's obviously always true if there is a single second-place CW.
*''Delegated votes are honest''. That is, voters do not delegate their vote to a candidate whom they disagree with. Though such a strategy might work in limited circumstances (when a candidate with exactly the right preferences was available to use to create a Condorcet cycle which didn't include themself), it would be both more trusting and risky than the average strategic betrayal, and also more cold-bloodedly dishonest. To exaggerate the case: how often are psychopaths good at trusting people?
The assumptions above would probably not strictly hold true in a real-life election, but they usually would be close enough to ensure that the system does elect the CW.
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== SODA-PR (obsolete; see [[PAL representation]]) ==
(Section obsolete;
==Compatibility with the US electoral college==
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Each "undelegated approval elector" would know the statewide non-delegated approval total, and the total of number of affiliated electors throughout the EC, for each candidate. Other "approval electors" would count as fractionally affiliated based on their known approval totals. These electors would be sworn to vote for whichever of the two candidates with the most nationwide electors had the highest statewide undelegated approval total. They would be chosen by the candidate for whom they were sworn to vote.
[[Category:Single-winner voting
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