[EM] STAR cloneproof variant based on Score Chain Climbing

[Ted Stern]

Reviving an old topic.

I had another thought for clone proofing STAR or Top Two Approval runoff,
based on SPAV or RRV. It is not summable.

Round one:

Approval or Score ballots.

Advance the top two approved or top two total score candidates.

Advance a third candidate using SPAV with Approval ballots or RRV if score
ballots, as if the two already advanced candidates were chosen by that
method. That is, if using approval, a ballot's weight for the third count
has weight 1 if it approved no previous winners, 1/2 if it approved one of
the first two winners, or 1/3 if it approved both the previous winners.
Similarly for score ballots using RRV.

If round one uses Approval ballots, a score ballot runoff will be held. If
using Score, the round one ballots can be recounted to find pairwise
preferences, using ratings to infer rankings. Or a separate score runoff
could also be held with the three winners, which I prefer.

In round two, use a cloneproof and burial resistant Condorcet method. Let's
say, score sorted margins or score chain climbing.

The difference from my first proposal is that there are always 3
candidates, representing either 2 factions, if top two are clones, or 3
factions, if not cloned.

My overall preference is for an approval first round, to eliminate most
candidates, then the cloneproof third candidate will generally represent a
different perspective to be debated before the runoff.


On Sat, Mar 12, 2022, 00:17 Forest Simmons <forest.simmons21 at gmail.com>
wrote:

> Thanks, Kevin. It was a comment of yours that made me realize that burial
> punishment (via chain climbing) was not enough ... but of course, looking
> away and pretending the burier was probably sincere ... that is no good
> either.
>
> So a sincerity check is natural ... if the sincere ballots contradict the
> strategic ballots, then in this case you have both detection and correction.
>
> Perhaps we could forget Chain Climbing and just use the sincerity check on
> the weakest defeat that was critical in determining the winner.
>
> El vie., 11 de mar. de 2022 11:42 p. m., Kevin Venzke <stepjak at yahoo.fr>
> escribió:
>
>> Hi Forest,
>>
>> Le vendredi 11 mars 2022, 23:03:30 UTC−6, Forest Simmons <
>> forest.simmons21 at gmail.com> a écrit :
>> > SCC:
>> >
>> > Initialize a variable X as the (name of) the lowest score candidate.
>> Then ...
>> >
>> > While more than one candidate remains, eliminate all of the candidates
>> pairwise
>> > defeated by X, before storing a new name into X, the name of the lowest
>> score
>> > remaining candidate.
>> > EndWhile
>> >
>> > The last value of X (the SCC winner Xf) is one of the finalists.
>> >
>> > The other finalist is the second to the last value of X, which we
>> designate Xf'.
>>
>> For the case that the initial value of X is the CW, should an elimination
>> order
>> be specified?
>>
>> > But doesn't the last X defeat all of the previous X's?
>> >
>> > Yes, according to the ballots. But there is a good chance that the only
>> reason
>> > Xf defeats Xf' on the ballots is that Xf' was insincerely buried under
>> Xf.
>>
>> In my terminology, that would mean Xf' is the sincere CW and Xf is the
>> "pawn."
>> The strategists' own candidate (the "rival") has been eliminated, so their
>> strategy failed (and would be a backfire, if the last X simply won).
>>
>> This probably implies that the sincere CW was unexpectedly the Score
>> loser.
>>
>> > So how do we vindicate (or expose as fraudulent) the finalist Xf?
>> >
>> > We could take another trip to the polls for a runoff between between Xf
>> and Xf'.
>> >
>> > Otherwise, we can require voters to submit two ballots ... one to
>> determine the
>> > two finalists, and the other to choose between them.
>> >
>> > Sincere voters simply duplicate their first ballot to produce their
>> second one.
>> > The strategy burdened voters adjust their insincerities to produce
>> their second
>> > ballot.
>> >
>> > It is crucial that the second ballot be used exclusively for choosing
>> the winner
>> > between the two finalists.
>> >
>> > However, once the final winner has been certified , these ballots can
>> be used
>> > for forensics.
>>
>> All true. It seems like the effect of this is to make "backfired strategy"
>> outcomes impossible. Is that the goal? It seems like that might risk
>> encouraging
>> voters to *try* burial strategies, unless it's sufficient to "name and
>> shame"
>> strategists through the forensics performed afterwards.
>>
>> It seems like this proposal could even prevent a backfire when *both* of
>> two
>> major factions are ranking the same pawn insincerely high, so that the
>> pawn
>> becomes the voted CW.
>>
>> Kevin
>>
>
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