IRV fails at Democracy
For no extra cost we could have
better ranked choice voting
counted by 'virtual round robin'

Instant Runoff Voting Fails at Democracy

If more people want A than B, A should win.

That's a pretty basic statement of democracy. Let's name it the majority principle.

Instant Runoff Voting can fail this.

In the 2009 March 3 election for Mayor of Burlington Vermont, an IRV election was held and it elected the wrong person.

Here's a histogram of how people voted on the candidates.

Andy Montroll
Rank	Votes
1	2062
2	2630
3	1398
4	497
5	119
votes	6706
average	3.897

Kurt Wright
Rank	Votes
1	2949
2	996
3	712
4	705
5	728
votes	6090
average	3.777

Bob Kiss
Rank	Votes
1	2586
2	1394
3	948
4	717
5	540
votes	6185
average	3.771

Dan Smith
Rank	Votes
1	1305
2	2102
3	1803
4	752
5	132
votes	6094
average	3.606

James Simpson
Rank	Votes
1	35
2	303
3	655
4	1041
5	1357
votes	3391
average	2.003

Write-in
Rank	Votes
1	38
2	46
3	42
4	44
5	73
votes	243
average	2.720

When I look at this table I see that Andy Montroll has pretty good 1st-choice support and even broader 2nd-choice support. Kurt Wright and Bob Kiss however are the favorite of substantial but narrow populations with less support at lower levels. However, because IRV only looks at the highest-ranked slot on a ballot, it misses this and produces the following sequence:

Round 1		Round 2		Round 3		Round 4		Round 5
Name	Count	Name	Count	Name	Count	Name	Count	Name	Count
Bob Kiss	2585.5	Bob Kiss	2599.5	Bob Kiss	2606	Bob Kiss	2982	Bob Kiss	4314
Kurt Wright	2952.5	Kurt Wright	2956.5	Kurt Wright	2963	Kurt Wright	3297	Kurt Wright	4064
Andy Montroll	2063	Andy Montroll	2067	Andy Montroll	2080	Andy Montroll	2554	Andy Montroll	2554
Dan Smith	1306	Dan Smith	1315	Dan Smith	1317	Dan Smith	1317	Dan Smith	1317
Write-in	38	Write-in	39	Write-in	39	Write-in	39	Write-in	39
James Simpson	35	James Simpson	35	James Simpson	35	James Simpson	35	James Simpson	35

There's more than one way to count ranked choice votes.

Here's what a virtual round robin election (Condorcet's method) result looks like:

		1	2	3	4	5	6
1	Andy Montroll		4067	4597	4573	6267	6658
2	Bob Kiss	3477		4314	3946	5517	6149
3	Kurt Wright	3668	4064		3975	5274	6063
4	Dan Smith	2998	3577	3793		5573	6057
5	James Simpson	591	845	1309	721		3338
6	Write-in	104	116	163	117	165

Andy Montroll was preferred over Bob Kiss by 4067 voters. 3477 voters had the reverse preference.

Andy Montroll was preferred over Kurt Wright by 4597 voters. 3668 voters had the reverse preference.

Andy Montroll was preferred over Dan Smith by 4573 voters. 2998 voters had the reverse preference.

Andy Montroll was preferred over James Simpson by 6267 voters. 591 voters had the reverse preference.

Andy Montroll was preferred over Write-in by 6658 voters. 104 voters had the reverse preference.

That first line below the table really says it all. In a head to head election, Andy Montroll should have beaten Bob Kiss by a 7.8% margin. A solid win.

More people wanted Andy than Bob, but IRV elected Bob. IRV failed the majority principle.

For no additional cost or complexity, using the same ranked choice ballots, we could instead use the 'virtual round robin' method of election (aka Condorcet's method) and get better democracy.

A year later, in 2010, Burlington voters repealed IRV