[Election-Methods] Borda-elimination, a Condorcet method for public elections?

[Dave Ketchum]

On Sat, 22 Dec 2007 19:46:07 -0000 James Gilmour wrote:
>>On Dec 22, 2007, at 6:45 AM, James Gilmour wrote:
>>
>>>If you wish to utilise in some way all the information that could be
>>>recorded on a preferential ballot, that is a completely
>>>different voting system from IRV, with different objectives.  The  
>>>preferences are no longer 'contingency choices', but take on a new
>>>function depending on the detail of the voting system.  It is almost  
>>>certain that the voters would mark their ballots in a different
>>>way in an election by such a voting system from how they would mark  
>>>their contingency choices in an election by IRV.
>>
> 
> Jonathan Lundell > Sent: 22 December 2007 19:00
> 
>>This seems plausible enough (and certainly IRV voters should be  
>>instructed along contingency lines). WRT marking ballots differently,  
>>setting manipulation aside, and considering only contingency vs  
>>preferential ranking, do you have an example or two of how and why a  
>>voter might end up with different ballots in the two contexts?
> 
> 
> That is a very fair question, Jonathan, but I do not have any practical examples to indicate the circumstances in which voters might
> mark their preferences differently.  We do not use IRV for any public elections in the UK and so I have no real example to draw on.
> And it is very difficult to invent examples based on direct, single-winner elections from other countries without a lot of relevant
> political information, because there is little agreement about how real voters would respond, as I have seen repeatedly in
> discussions of such examples as Bush-Nader-Gore.  I am not a specialist in voter behaviour and so have no special insights on which
> to base "real" predictions.
> 
> That said, one situation where IRV ballots and Condorcet ballots might be completed similarly would be when there are three strong
> front-runners.  Then IRV voters and Condorcet voters might well complete their preferential ballots similarly.  When the "everyone's
> second choice" candidate had very weak first preference support, they might well complete the ballots differently: in Condorcet the
> supporters of the two strong wings might truncate in an attempt to prevent the weak second choice from coming through the middle.
> But that suggestion is contentious, as I have seen in other discussions and there is no agreement about how voters would really
> react.
> 
> Just a word about terminology: IRV ballots, Condorcet ballots and Borda ballots are all 'preferential' ballots.  The difference is
> that in IRV the successive preferences are brought into play only on the stated contingency; Borda tries to sum all the preferences
> instantly into one value; Condorcet perhaps lies somewhere between these two extremes, depending on the sequence of events in the
> individual count.

Out of all this I see very little possible use for differences:
      All three want the same information about ranking.
      Borda extracts numeric rank information - which it can get from the 
same ballots.
      Condorcet can and should permit equal ranking of multiple candidates 
- presumably foreign to the others.
> 
> James Gilmour
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