[EM] Why I Prefer IRV to Condorcet

[Juho Laatu]

#1
- If your target is to elect Condorcet winners methods that meet Condorcet criterion could be considered.

#2
- There are also simple Condorcet methods like "elect the one that needs least additional votes to win all others".
- It is also a fact that in many countries few voters actually know and care about the internal details of the method. IRV and Condorcet may look quite similar to them.

#3
- I don't think _rational_and_successful_use_ of Condorcet strategies is intuitive to the regular voters.
- Some voters may however follow proposed strategies even if they are irrational (also in IRV).
- IRV has its problematic scenarios too (like you shortly mentioned).
- In large public elections with independent decision making, inaccurate poll information, changing opinions, and less than 100% penetration of strategic voters many strategic vulnerabilities of Condorcet become difficult to apply (or are not probable). Many strategies are easier to carry out on paper and with exaggerated votes and exaggerated voter behaviour than in real life. Each example should be analysed in detail but I'll skip that for now.

#4
- One simple approach for A and B would be to sling mud on C too. C seems to be a potential winner (maybe even a sincere Condorcet winner) so one should definitely not let him just hide (if mud is generally used).
- I think all candidates want all kind of support (core or other), also in Condorcet although only IRV requires strong core support.
- Hiding candidates may be seen as weak candidates, and therefore also Condorcet candidates need clear statements and a profile.
- Also in IRV candidates should try to please all the voters to get second preferences (they are important too although first preferences are a must).
- No big difference between candidate behaviour. In IRV candidates with limited first place support are not likely to be successful.

#5
- Yes, the methods could pave the way for each others. IRV leads in the U.S.. so it may help more.

#6
- I don't see a big difference between IRV+STV and Condorcet+STV. Ranking based single winner methods should be a good enough stepping stone for ranking based multi winner methods. Political will may be more important than the internal details of the methods.
(- Legal battles might be another thing, and that is a risk in the U.S.)
(- Also other good multi winner methods than STV exist.)

#7
- Yes, IRV seems to be ahead in the U.S.
- People may be familiar with runoffs, but also with tournaments


Many of the reasons didn't say that IRV is a better method than Condorcet but focused on other benefits of IRV (or on how it can help Condorcet). Strategic vulnerabilities seemed to be the central point when comparing the actual methods. The vulnerabilities of the two methods are different. I don't think Condorcet is essentially more vulnerable in typical public elections.

Also performance with sincere votes should have some weight. Electing a "wrong" candidate with sincere votes doesn't look nice. If election of Condorcet winners is the target then one could try to guarantee that.

In some places voters are happy to vote as told by strategists and use whatever tricks there might be. In some places strategic voting is not considered to be good behaviour. Also individuals are different. One could use methods with suitable resistance against strategies or methods that pick good winners depending on the expected strategic behaviour level of the environment. (One could also change the method to a better one if one sees that fears of widespread strategic voting did not materialize, or the other way around.)

IRV and Condorcet promoters could indeed cooperate more. IRV is not that bad, and Condorcet certainly neither. The disagreeing promoters (trying to kill the campaigns of each others) may actually be one of the biggest problems slowing down progress in the U.S. Condorcet has also the problem that it has different variants and no consensus on which one is the best.

The serial elimination process of IRV may be appealing to the voters (looks like a good fight where some super hero remains last) but due to its semi-random nature (see e.g. the Yee diagrams) it can't be considered to be optimal. IRV is however an improvement when compared to many methods in use today.

I tried to be brief. Ask for clarifications if I was too brief somewhere.

Juho



--- On Wed, 19/11/08, Greg <greg at somervilleirv.org> wrote:

> From: Greg <greg at somervilleirv.org>
> Subject: [EM] Why I Prefer IRV to Condorcet
> To: election-methods at electorama.com
> Date: Wednesday, 19 November, 2008, 11:28 PM
> I have written up my reasons for preferring IRV over
> Condorcet methods
> in an essay, the current draft of which is available here:
>   http://www.gregdennis.com/voting/irv_vs_condorcet.html
> 
> I welcome any comments you have.
> 
> Thanks,
> Greg
> ----
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