[EM] The general form of Quick Runoff

[Juho]

True, I missed the "majority" part.

Juho


On May 24, 2010, at 10:38 AM, C.Benham wrote:

>
> Juho wrote (23 May 2010):
>
> <snip>
> > 1. Rank the candidates. Truncation is allowed. Equal ranking is not
> > planned for (but we could come up with something).
> > 2. Label the candidates A, B, C, ... Z in descending order of first
> > preference count.
> > 3. Let the current leader be A.
> > 4. While the current leader has a majority pairwise loss to the very
> > next candidate, set the current leader to the latter candidate. (In
> > other words step 4 must be repeated until there is no loss or no  
> other
> > candidates.)
> > 5. Elect the current leader.
>
>> How about this example and LNH.
>>
>> 6: A>C
>> 5: B>A
>> 2: C>B
>> 2: C
>>
>> Candidate names indicate the order in first preferences. B beats A. C
>> beats B. C wins.
>>
>> 6: A>C
>> 5: B>A
>> 2: C>B
>> 2: C>A
>>
>> Two "C" voters have changed their vote to "C>A". B does not beat A. A
>> wins. The "C" voters were harmed when they included their later
>> preferences.
>>
>> Juho
>>
>>
>
> Juho,
>
> The key word you missed in the definition is "majority". In both  
> your elections there are 15 ballots, so a
> "majority pairwise loss" requires a winning score of at least 8.
> In both cases the FPP winner A wins, in the first because B's  
> pairwise score against
> A is 7, a pairwise win but not a "majority" pairwise win (and so of  
> course not a
> "majority pairwise loss" for A).
>
>
> Chris Benham
>

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