On Jan 13, 2010, at 4:49 AM, Juho wrote:
On Jan 13, 2010, at 9:14 AM, robert bristow-johnson wrote:
it still is a curiosity to me how, historically, some leaders and
proponents of election reform thunked up the idea to have a ranked-
order ballot and then took that good idea and married it to the IRV
protocol. with the 200 year old Condorcet idea in existence, why
would they do that?
1) The basic idea of IRV is in some sense natural. It is like a
street fight. The weakest players are regularly kicked out and they
must give up. I'm not saying that this would lead to good results
but at least this game is understandable to most people. Condorcet
on the other hand is more like a mathematical equation, and the
details of the most complex Condorcet variants may be too much for
most voters. Here I'm not saying that each voter (and not even each
legislator) should understand all the details of their voting
system. The basic Condorcet winner rule is however a simple enough
principle to be explained to all. But it may be that IRV is easier
to market (to the legislators and voters) from this point of view.
When there is a CW in Condorcet, the CW has won in comparison with
each other candidate. While a few may like X or Z enough better to
have given such top ranking, the fact that all the voters together
prefer the CW over each other should count, and does with Condorcet.
Else there is a cycle in Condorcet. Perhaps the following Minimum
Margins Method Condorcet variant should be used to establish
Condorcet's preferability over other methods. Then let other variants
compete with this one before finally deciding which to use.
Minimum Margins Method: Consider the cycle, such as A>B>C>A, and the
margins that create it, such as 60A>30B, 40B>20C, 21C>20A. Delete the
weakest margins as many times as needed to destroy the cycle - in this
case A becoming the CW (note that if one C>A voter had voted A>C in
this election, A would have become CW with no cycle).
2) IRV is easier to count manually. Condorcet gets quite tedious to
count manually when the number of candidates and voters goes up. One
can use some tricks and shortcuts to speed up manual Condorcet
counting but IRV probably still beats it from this point of view.
Manual counting was the only way to count for a long time. Nowadays
we have computers and Condorcet tabulation should thus be no problem
at all (at least in places where computers are available). But this
is one reason why IRV has taken an early lead.
When an election district has only one polling place, life is simple.
When the district is a state or city, life is more complex for each
method.
With IRV you first want top ranks from all the ballots in the
district. If there is no majority winner all the ballots for the
worst loser must be scanned for all the polling places for whom those
voters ranked next. Repeat until winner gets decided.
With Condorcet each ballot gets scanned one time and its content
added into an N*N array, with such arrays summed for the whole district.
3) Large parties are typically in a key role when electoral reforms
are made. Election method experts within those parties may well have
found out that IRV tends to favour large parties. In addition to
trying to improve the society the best way they can, political
parties and people within them also tend to think that they are the
ones who are right and therefore the society would benefit of just
them being in power and getting more votes and more seats. The
parties and their representatives may also have other more selfish
drivers behind their interest to grab as large share of the power as
possible :-). IRV thus seems to maintain the power of the current
strongest players better than Condorcet does, and that may mean some
bias towards IRV.
4) The problems of different election methods may appear only later.
A superficial understanding of IRV reveals first its positive
features. Like in Burlington the negative features may be understood
only after something negative happens in real elections. This
applies also to Condorcet. On that side one may however live in the
hope that the problems are rare enough and not easy to take
advantage of so that sincere voting and good results would be
dominant. The point is that IRV may be taken into use first (see
other points above and below) without understanding what problems
might emerge later. And once it has been taken into use it may well
stay in use for a long time (electoral reforms are not made every
year, people have already gotten used to the method, having to
change the method could be seen by the society/legislators as a
failure/embarrassment, and people/parties who were elected based on
those rules and are strong in that system may be reluctant to change
the rules).
5) Both IRV and Condorcet have some weak spots that can be attacked.
As you point out the weak spots of IRV may well be worse than those
of Condorcet methods (for most typical use cases in politics).
Different problems may have different weight in different political
environments. For example in countries with strong two-party
tradition and single party government some Condorcet properties like
the possibility of electing candidates that do not have strong first
preference support in the ballots may work against it (both in the
case that one does not want the system to change and in the case
that one wants to renew the system). Also strategic voting and fraud
related problems (like later no harm, burial, precinct counting) may
be seen in different light in different societies, e.g. in countries
where strategic voting is the norm vs. in ones where sincere voting
is the norm. One may thus have/develop points of view where
Condorcet looks worse than IRV (I guess it could also be worse for
some uses in some societies from some points of view).
So some whose backers tend to rank them top object when they lose
because more other voters rank them below others? I like better
Condorcet's having A win over B when more voters prefer A>B to B>A
without caring which is top ranked by more.
single party government? If some voters rank B>A and some rank C>A, A
still wins if the total is A>B and A>C. Good to get vote counts that
identify what A is seen as doing well, and what it had better improve.
Juho
P.S. One more reason is that Condorcet promoters seem to be lazier
that IRV promoters :-). Condorcet has made some progress in the
academic circles but not yet in politics.
Agreed, though this is not a reason why IRV deserves to win this race.
Dave Ketchum
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