# [Election-Methods] Is this Condorcet method reasonable?

Dave Ketchum davek at clarityconnect.com
Sun Dec 2 07:23:13 PST 2007

```Agreed margins is better, though I do not see this test case as proof.

Also, rules should be neutral as to promoting or discouraging truncation.

AND, rules should be simple, to promote voters being able to understand them.

I happily throw darts at IRV, noting that Condorcet is summable, while its
cousin, IRV, is not.

On Fri, 30 Nov 2007 10:06:32 -0300 Diego Santos wrote:
> There were many discussions in this mailing list about advantages of
> winning votes as counterstrategy against order reversal. But sometimes
> truncation is risky. Consider this example:
>
> 46: A > B > C
> 44: C > B > A
> 10: B > A > C
>
> B is CW.

Agreed.
>
> Offensive strategy by A voters:
>
> 46: A > C > B
> 44: C > B > A
> 10: B > A > C
>
> A wins under RP(wv) or margins.

??? A voters say they like C better than B - suspicious for, to me, this
makes a cycle with C winning (90>10 voters prefer C>B; 56>44 A>C; 54>46 B>A.

C voters could do the same for A.
>
> If truncation would be used:
>
> 46: A > C > B
> 44: C > B > A
> 10: B
>
> C, the sincere Condorcet loser, wins.

Agreed - but C wins due to A voters' change.  B voters' change from A>C to
A=C is too trivial to matter.
>
> Winning votes induces truncation. Voters should feel free to express
> complete preferences.
>
> I was thinking in something similiar to "automatic truncation", i. e.,
> pairwise stregth in ranked pairs should be measured by plurality. If
> approval is used, the method becames DMC. Maybe approval cutoffs are not
> needed, then RP(plurality) is sufficient.
>
> RP (plurality)  or pairwise sorted plurality offers weak burial
> resistance and is summable, opposite to Smith,IRV.
>
> Diego Santos
>
>
> ------------------------------------------------------------------------
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Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
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