[EM] Random and reproductible tie-breaks

[Stéphane Rouillon]

I erred if I wrote it is ridiculous to nominate clones unless one can 
predict before the election that a
tie will occur.

What I tough I wrote is : it is ridiculous to bother with an clone 
independent tie-breaker if one considers a clone dependent electoral system.

Using a Condorcet method for example ensures a clone independent resolution, 
thus different computers should always end up to the same winner despite 
ties if they both use the same reproductible (but equiprobable or fair) 
tie-breaker.

Although I have a lot of admiration for Forest and Jobst work, I cannot 
accept the use of random non-reproductible ballot selection for tie-breakers 
(or for winner designation even more) because it kills the validation of the 
process. If the process of designation of the winner can be repeated ad 
nauseam, fraud can be achieved only by corrupting the ballots database. It 
then becomes a lot easier for electoral managers to ensure an honest result.

In the other case, anyone should be able to know in advance how the random 
ballot is selected to thrust the electoral process. If it uses a definite 
predictible and reproductible method, frauders will try to get several 
favorable ballots as the tie-breaking numbered ballot.  If it uses a 
non-reproductible method, frauders will try to taint that one time process. 
Thus I favor unpredictible but reproductible (but still equiprobable) 
tie-breakers as the one presented previously, which works for small groups 
and without any opportunity to influence a chairperson. It is random only 
because it uses the election data which nobody should know in advance.

>From: Steve Eppley <SEppley at alumni.caltech.edu>
>To: election-methods at electorama.com
>Subject: Re: [EM] Random and reproductible tie-breaks
>Date: Mon, 29 Sep 2008 06:36:50 -0700
>
>Hi,
>
>Raph Frank wrote:
>>Stéphane Rouillon <stephane.rouillon at sympatico.ca> wrote:
>>
>-snip-
>>>  Tie-breakers have no need to be clone-independent. You cannot predict a 
>>>tie
>>>will occur
>>>  before the election and it would be ridiculous to strategize on this
>>>hypothesis.
>>>
>>
>>In fairness, tie breaks are a low probability issue in any case.  If
>>you are going to do them right, you might as well do them fully right.
>>
>
>Raph seems to be saying it's just an aesthetic value for the tiebreaker to 
>be independent of clones.  I believe it's not just aesthetic.  Stephane 
>erred when he wrote it is ridiculous to nominate clones unless one can 
>predict before the election that a tie will occur.  All that's needed for 
>nominating clones to be strategically sensible, assuming the cost of 
>nominating clones is low, is that the probability of a tie is not 
>negligible.  The probability of a tie is typically not negligible when 
>voting within small groups (committees, councils, legislatures, etc.) and 
>the cost of nominating clones in small groups is typically tiny, which 
>means it can be strategically sensible to nominate clones if the tiebreaker 
>is not independent of clones.  It's a form of insurance against a low 
>probability undesired event.
>
>Even if one's focus is on large public elections, before asking the public 
>to adopt the method in public elections it may be crucial for the voting 
>method to first develop a track record of satisfaction among many small 
>groups.  Hence the tiebreaker ought to be independent of clones (or should 
>be close enough to independent that the probability of gaining by 
>nominating clones is negligible).
>
>I don't know that the tiebreaker used within small groups must be identical 
>to the tiebreaker that would be advocated for large elections.  For 
>example, in small groups a seniority system is common; typically a 
>chairperson casts the tiebreaking vote.  Fortunately for us, that 
>tiebreaker provides clone independence with repeatability and no 
>randomness.
>
>Here's another tiebreaking option.  It's typical for groups to choose the 
>status quo alternative when it's tied.  Perhaps it would be acceptable to 
>break ties based on the order of nomination (treating the status quo as 
>first nominated, when it's an alternative).  This tiebreaker wouldn't 
>provide a strict independence of clones, I think, but it may be near enough 
>to clone independent to make it strategically hard or pointless to nominate 
>clones.  It too has the desirable attributes of repeatability and 
>non-randomness.
>
>In a more recent message in this thread, Raph wrote:
>>Also, if there was a tie, then odds are that there is only 2 people
>>involved, so it doesn't really matter about clones.
>>
>
>I don't understand why Raph wrote that.  Assume a tie involves two 
>alternatives, and assume the voting method (up to but not including the 
>tiebreaker) is independent of clones.  By nominating clones of one (or 
>both) of the two tied alternatives, the tie can be changed so it involves 
>more than two.  It follows that it can matter whether the tiebreaker is 
>independent of clones.
>
>Regards,
>Steve
>----
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