# [EM] Re: IRV for president: 2 votes overpower 105 million

Craig Carey research at ijs.co.nz
Mon Jul 14 11:30:14 PDT 2003

```At 2003-07-14 09:22 -0700 Monday, Rob LeGrand wrote:

>Craig Carey wrote:
>>    +----------------------------------+  -------------------------
>>    |  A     50,000,001   199,999,999  |   20.0000004  49.99999975
>>    |  BA    49,999,999    50,000,001  |   19.9999996  12.50000025
>>    |  CB   100,000,000   100,000,000  |   40          25
>>    |  DBA   50,000,000    50,000,000  |   20          12.5
>>    +----------------------------------+  -------------------------
>>  Winner:             A             B
>>  Total:    250,000,000   400,000,000
...
>Craig seems to be
>saying that IRV is defective because it chooses B instead of A in the
>second election.  I'd say that IRV is defective because it chooses A
>instead of B in the first election, in which almost 80% of the voters voted
>B over A.  B is the Condorcet winner in the second election, so IRV
>stumbles upon the correct choice in that case.
...

I didn't indicate an opinion for these 3 options: the Alternative Vote (AV)
got the 1st wrong, the 2nd, or both.

My guess is that C wins the 1st, and A wins the 2nd.
Tests of correctness of methods seem to give interesting results but it
can't be done here.

That follows from FPTP-izing the examples. Possibly monotonicity would
always drag towards FPTP. The tilt-changes may vary.

---------------

(Is this mailing list dumb?: why is there a thread on Arrow's
pseudo-theorem.)

Craig Carey

```