[EM] The truth about Instant Runoff Voting

[RLSuter at aol.com]

This is something I posted on an anti-war list in response
to the post of an editorial advocating IRV. There is
nothing new here for most people on this list, but some
people may find it worthwhile to post to other lists.
I assume that little if anything I say here will provoke
controversy on this list, but if you think I've gotten
anything wrong, don't hesitate to say so.


-Ralph Suter


The truth about Instant Runoff Voting

A recent newspaper editorial advocating Instant Runoff
Voting began as follows:

   What if we were able to streamline our 
   city and town elections, make them less 
   expensive, and at the same time, ensure 
   that the winner garnered a majority of 
   more than 50 percent of the vote? [1]

   What if we were able to streamline our 
   city and town elections, make them less 
   expensive, and at the same time, ensure 
   that the winner garnered a majority of 
   more than 50 percent of the vote? [1]

The truth is that Instant Runoff voting (widely known by
the abbreviation IRV) can't come close to ensuring this.
The only way a candidate can be said to have won a majority
of the vote is if it can be shown that she or he would
defeat every other candidate in a one to one contest.
Voting experts have a name for such a candidate: the
"Condorcet" winner, named after the 18th century French
mathematician, political philosopher, and activist (he
lost his life in the French revolution) who is now best
known for his advocacy of what is now widely called
Condorcet voting.

A better name for Condorcet voting would be "instant round
robin voting" (call it IRR). The IRR method would use the
same kinds of ranked ballots as IRV and therefore would
require the same kinds of voting equipment. (Both would,
for all practical purposes, require computerized vote
tabulators, because tabulating either IRV or IRR elections
by hand would be prohibitively time consuming and prone
to human error.)

The one difference between the two methods -- and it is
a very big difference -- is in how the ranked ballots
are tabulated to determine the winner. The basic concepts
are very simple. With IRV, the ballots are tabulated to
simulate a series of runoff elections. As soon as a
candidate gets a majority in one of those simulated
runoffs, that candidate is declared the winner.

With IRR, the ranked ballots are tabulated to simulate
contests between each candidate and every other candidate.
If one candidate defeats every other candidate in those
simulated contests, that candidate is declared the winner.
Such a Condorcet winner is the only candidate who can
ever be said to have truly "garnered a majority of more
than 50% of the vote."

The problem is that both IRV and IRR have well known
weaknesses. In fact, voting experts have long known that
there are no voting methods for choosing among three or
more candidates that have no weaknesses. Therefore, voting
method researchers try to find methods that have the
fewest or least objectionable weaknesses.

The big problem with IRV is that the winner is very often a
candidate who would have lost to one or more of the other
candidates in a one to one contest. This is not just an
occasional problem but would likely happen frequently.

The big problem with IRR is that sometimes there is no
candidate who will defeat each of the others. In such
cases, no matter which candidate is declared the winner,
there would be at least one other candidate who would
defeat the declared winner in a one to one contest.

No one can say for sure how often these problems would
occur in actual elections run with either IRV or IRR. My
guess is that a non-majority IRR winner would be much rarer
than a non-majority IRV winner. But advocates of IRV might
disagree, or they might say it doesn't matter because IRV
is superior to IRR for a variety of reasons. I won't try
to settle that disagreement here.

Unfortunately, advocates of IRV, IRR, and some highly
regarded non-ranking methods that have the advantage of
being much easier to tabulate (most notably, Approval
Voting), almost never get to debate except among very
small groups of specialists. The biggest organizational
advocate of IRV, the Center for Voting and Democracy,
has essentially prohibited debates under its auspices.
Its leaders almost never engage in debates except when
necessary to respond to articles in prominent publications
such as Science News [2] and Scientific American [3]
in which different methods are advocated or favorably
discussed.

In short, Instant Runoff Voting is not the panacea its
advocates have made it out to be. If IRV advocates are as
serious about democracy as they claim to be, they will
cease to be merely advocates of a particular voting method
but will also advocate and participate in honest, public,
democratically conducted debates between IRV advocates
and advocates of other voting methods.

Ralph Suter

(An attendee of the 1992 founding meeting
of the organization that later became the
Center for Voting and Democracy)

[1]"Runoff vote system makes good sense", Southwest
Florida News Press, January 3, 2005, www.news-press.com/
apps/pbcs.dll/article?AID=/20050102/OPINION/501020401/1015

[2] "Election Selection: Are we using the worst voting
procedure?", Science News, November 2, 2002, p. 280.
www.sciencenews.org/articles/20021102/bob8.asp
[mainly about Approval Voting]

[3] "The Fairest Vote of All", Scientific American,
March 2004, www.sciam.com  [mainly about Condorcet 
voting, which is called "True Majority Voting" in the
article]