[EM] IRV proponents figure out how to make IRV precinct-summable
raphfrk at gmail.com
Tue Mar 24 07:28:58 PDT 2009
On Tue, Mar 24, 2009 at 2:30 AM, Dave Ketchum <davek at clarityconnect.com> wrote:
> Let's try it slowly for IRV, assuming multiple districts to avoid shortcut
> 1 Count ala Plurality. If leader has a majority, that is winner.
> 2 Sum vote counts, starting with weakest count and ending before doing the
> next candidate that would make a majority. None of those counted could win,
> so mark them all as losers and go back to step 1.
That isn't true.
The rule is actually that you can eliminate the weakest N candidates
in one step, if the sum of their votes is less than the (N+1)th
weakest candidates. The procedure is then to find the largest
According to your rules, eliminate F+E+D+C. Eliminating B as well
would cause a majority of votes, so B is safe.
However, with full IRV, the results are
E: 7+4 = 11
E: 9+11 = 20
E: 20+15 = 35
E: 35+25 = 60
So, the result is different.
>> Less formally, the method is summable if you can "count in precincts" to
>> produce managable data chunks that can then be combined to get the result
>> for all precincts or districts involved, no matter the size of each
> Not clear how this helps. You have to get the totals for round 1 to decide
> how to proceed - matters not how many chunks.
I guess IRV is "summable in precincts, subject to central office instructions".
An election can be verified by checking all the precinct sums/counts
and that the central instructions were correct, assuming that the
precinct sums were also correct.
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