Posts by Steve Todd
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Legal Beagle: Voting in an STV election, in reply to Brent Jackson,
Have a look at this paper, Brent: http://www.votingmatters.org.uk/ISSUE13/P4.HTM.
I think you want STV with equality of preference. It can be done. David Hill's STV program provides for it, but he only allows a maximum of 10 candidates having the same EQP. If you provide for much more than that, certainly 35 or more candidates able to have the same preference number, you get a "combinatorial explosion" that computers, even today, might not be able to cope with.
Plus, the 'Instructions to Voter' are more complicated. I've done a draft and can confirm that.
I think we all have to keep in mind that we are talking about public elections here. Showing the results of EQP STV elections would be greatly more problematic than it is for NZ (Meek) STV elections. I like EQP STV, but, at this point, I would only recommend it for private elections.
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Legal Beagle: Voting in an STV election, in reply to Graeme Edgeler,
I’m absolutely fine with STV, and what anomalies remain don’t really concern me either.
Graeme, rest assured, I have never doubted that you are, at the very least, very kindly disposed towards STV. You wouldn’t do what you do here, and make the supportive comments about STV here and elsewhere, that you do, if you weren’t. I, for one, am extremely grateful to you.
We know that all electoral systems have to suffer from some anomaly or other, but STV does have the following advantages that no other electoral system used in public elections, that I know of, has—
(A) The number of ‘wasted’ votes in an election (i.e., which do not contribute to the election of any candidate) is kept to a minimum.
(B) As far as possible the opinions of each voter are taken equally into account.
(C) There is no incentive for a voter to vote in any way other than according to his or her actual preference.Happily, NZ STV, with its iterative feedback mechanism (and the consequent reduction in the quota as additional votes become non-transferable, i.e. drop out of the election, as voters, in effect, exercise a delayed abstention), fulfils these conditions, particularly condition (B), much better than traditional STV methods.
In fact, I consider NZ STV is about as far as we can go in the refinement-manageability-public understanding trade-off in the single transferable vote. I think the notion that STV, with further advancements, being used in public elections, will have to wait until everyone has PhDs in pure mathematics and political science!
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But, like nonmonotonicity, the no-show paradox, etc., G-S can only be demonstrated with artificial examples. STV's so-called defects are not properties, if that's the right word, that ordinary voters in large public elections can in any way take advantage of.
I'm obviously biased, but, although they're all very interesting, they're ultimately meaningless when it comes to public elections.
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Legal Beagle: Voting in an STV election, in reply to Tim McKenzie,
Do you really want to insist that this would be the correct result, even though more than three quarters of all the voters would have preferred E to win?
Yes, I do want to insist that. If more than three-quarters of voters preferred E to win, then why didn’t they vote for E. The simple fact is only 10 voters wanted E to win, the other 398 didn’t. They all voted for candidates other than E – “You have one vote, which you express by giving your first preference to the candidate *for whom you vote*. The argument I laid out, stands. Second and later preferences are contingency choices only, etc., etc.
I put up that voting pattern to show that, even though E is the Condorcet candidate, s/he cannot realistically, in a public election, be regarded as the correct winner. Yet, here you are, effectively arguing that s/he is. Astonishing!
If pre-election polls indicated that this was likely to happen, would the supporters of B, C, and D really have had “the confidence to rank-order the candidates in their true and genuine order of preference”, or would they have decided to tactically give their first preferences to E, in order to deny A the unpopular victory over E?
And here we get to the nub of the issue. People like you (e.g. Doron and Kronick, et al) argue your case, using carefully constructed artificial voting patterns. You argue points that would never be in the minds of voters when they vote. You point out so-called anomalies, that no voter, not having knowledge of precisely how other people are going to vote, could never take advantage of in real, public elections.
The polling you refer to, above, is “artificial”. Polling in STV jurisdictions has never unearthed a candidate that was everyone’s second choice, because they don’t exist in real life, and never will. Had such a candidate ever been identified, the voters in the jurisdiction concerned would certainly have been told about it.
No-one is ever everyone’s second choice, just as no-one is ever everyone’s first choice, or third, or fourth choice. In the real world, voters just aren’t like that.
The best we can hope for is two-candidate-preferred (2CP) polling, such as that which I suggest here: http://wellington.scoop.co.nz/?p=91188#comment-949241. (See my second comment, 6 August, at 20:44 hrs.) Unfortunately, after 12 years, it would seem we are no closer to having such polling than we were in 2004.
No election method used for public elections anywhere in the world sets out to find, and elect a compromise candidate. The purpose of elections is to enable people to elect their representatives, not to arbitrarily discard candidates who “stand for something” in favour of *compromise* candidates. Any method that elected “everyone’s second choice” in a real, public election, would almost certainly be thrown out at the first opportunity.
It astonishes me that you continue to pick away at a perceived fault of STV (which is used in public elections in many places around the world), which can only be remedied by accepting another fault, but you don’t argue for *your* preferred system (which, whatever it might be, we know is not used in public elections anywhere), explaining why it is better than STV. How about you do so.
Of course, you’re not going to do that – you might expose yourself to ridicule – so how about at least explaining to us why you are “still not persuaded that later-no-harm is more important than having majority support for the winner, wherever possible.” Explain to us why it is worthwhile to give up later-no-harm so that the majority winner – let’s call it the Condorcet winner – is elected 100% of the time, instead of 99.9% of the time.
Then, while you’re at it, explain to us what you mean by this elitist clap-trap, “And in multiple-winner STV elections, later-no-harm seems likely to harm voters’ preferences over the sets of possible winners.”
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Legal Beagle: Voting in an STV election, in reply to Tim McKenzie,
Later-no-harm insists that a particular kind of tactical voting is unnecessary and impossible.
Does it. Why not explain how?
But why is it more important to rule out that kind of tactical voting, while ignoring all the other possible kinds?
As previously stated, it gives voters the confidence to rank-order the candidates in their true order of preference. When that is done, the outcome represents the true, collective, wishes of the voters, when taken as a whole. Surely, that is a good thing.
And is it worth it if it means that a voter’s preference between their two favourite candidates is always treated as more important than their preference for their second-favourite candidate over their least-favourite candidate?
Yes it is. Why would it not be?
Why not insist instead that the system should ensure that a voter’s best strategy (or at least one of their best-equal strategies) always involves ranking their favourite candidate first? STV certainly doesn’t have that property, and I wouldn’t be surprised if it was incompatible with later-no-harm.
That is exactly what STV does. As there is no incentive for voters not to vote their true preferences, it logically follows that STV most certainly must have the ‘rank-the-most-favoured-candidate-first’ property.
What a nonsensical statement. What proof do have that STV “certainly doesn’t have that property?”
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Legal Beagle: Voting in an STV election, in reply to Paul Campbell,
Here I have to disagree – your second and subsequent preferences are more than contingency choices … for example if you and your neighbours give candidate A twice as many votes as they need to be elected then a full 1/2 of your vote is still live and will pass to your second choice, and will keep being passed down your preferences until it is used up …
Oh, Paul, that is basically the start of the “official” description of how you vote in an STV election. They most definitely are contingency choices.
What you are describing, is the effect the vote has on the election, at the end of an NZ STV count. At the beginning, when people are actually voting, they (theoretically, at least) say to themselves the passage that you disagree with.
If you look at the extended example I linked to in my reply to Tim, you will see (in column 5) that the first-preference candidate (A) kept none of the vote, the second-preference candidate (B) kept 47.72% of it, and the third-preference candidate (C) kept 36.73% of it, and on down the list.
When this vote was cast, the voter was voting for A. At the end of the count, it can be seen that with A having been excluded, the vote transferred to elected candidate B, the surplus portion of which passed over excluded candidate C and landed upon elected candidate D, who only needed 70.26% of it.
So, yes, the vote substantially contributed to the election of two candidates, and contributed in a minor way to the election of several others. But that is just a happy consequence of the way the votes in this election were cast (and the fact that they were counted by the far more efficient NZ STV method). It was not the voter’s original hope that it might, or intention that it would, be used in this way.
In this regard, each individual voter has no way of knowing how his or her “neighbours” are going to vote. All he or she knows is that s/he’s voting for A, with the expectation that if A doesn’t need all of it, or is excluded from the count, it will be transferred, in whole or in part, to B, and so on, until it hits a candidate whose (final) keep value is 1.0.
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Legal Beagle: Voting in an STV election, in reply to Rich of Observationz,
And it appears to limit the ability to change the alignment of councils - if there's a Green, Labour and National candidate with name recognition and good campaigns, they'll all get elected even though the Green might be on 40% and the Nat on 25%.
Rich--
Have a look at my response (and two replies) to Cr Simon Woolf, here:
https://www.facebook.com/OnslowWestern/posts/1069826773085165:0
My response is immediately under his post.
The problem you describe is known as electoral stasis. The answer, in my view, is to elect our council citywide (at-large).
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Legal Beagle: Voting in an STV election, in reply to Paul Campbell,
I think it’s really smaller than that as it only requires half that many mistakes to turn it around.
No, by the end of the count, those 43 votes (approx.) will be the difference between the 2,535.817272399 votes (across several thousand voting documents) for Colin Weatherall, and the 2,492.840680897 votes (also across several thousand voting documents) for Bev Butler.
Colin and Bev received 1,236 and 1,234 first preferences, respectively. The additional 1,300 votes and 1,258 votes, respectively, they each received, will be made up of tiny bits of votes, on perhaps as many as three or four thousand voting documents. There would have to be vote-entry errors on hundreds, perhaps over a thousand, voting documents, for those little bits to affect the count, through 58 iterations, in such a way as to elevate Butler above Weatherall. It's not just a matter of there being 22 errors in entering first-preferences for Butcher that should have gone to Butler.
But think about it. Would the DEOs give lots of Butler's '1's to Butcher, immediately above her on the voting documents? How would that happen? As previously explained, the DEOs carefully insert, beside the hand-written number, what that number is. It is not possible to see a hand-written '1' beside Butler's name, but insert a '1' beside Butcher's name. The DEO has moved on past Butcher.
Then, of course, if so many mistakes were made, affecting two candidates consecutively listed on the voting documents, then there would have been many other entry errors in respect of other candidates, too. But there weren't.
The computer technology needed to process votes electronically probably precludes every STV council having their own facilities. Those days are gone. electionz.com is doing Wellington's votes, too. I'm sure we will be posting our votes to Christchurch, as well. With OCR technology, the role of scrutineers is basically done away with. They were needed when the votes were literally hand-counted, and even when they were 'wanded' into the computer, but not now.
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Legal Beagle: Voting in an STV election, in reply to Tim McKenzie,
Tim, a voter may well want both A and B to win, but that is not the point. Under STV, every voter has one vote, which they express by giving their first preference to the candidate *for whom they vote*.
Second and subsequent preferences are contingency choices only, whereby the voter is saying (to the electoral officer / STV calculator), if my first preference candidate does not need all of my vote, or is excluded from the count, I want my vote to be transferred, in whole or in part, as the case may be, to my second preference candidate, to help elect that person, and so on.
So yes, STV does place a "heavy weight on your higher preferences", because that is what it is supposed to do - it is, after all, a single-vote system, not a multi-vote system.
See, at my first posting, above, page 3 of the paper at the third link, to see how a vote is used in an NZ STV election. A multi-candidate example can be seen here:
https://dunedinstadium.wordpress.com/2010/08/22/why-not-the-stv-voting-sytem/
Go to my reply to 'ro', at September 22 at 7.54 a.m., then click on the vote_example link at the conclusion of my comments. You will see how the amount of the vote that is kept by each candidate falls away very quickly, exactly as it should.
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Legal Beagle: Voting in an STV election, in reply to Graeme Edgeler,
But it’s a judgment call as to what particular criteria you want a voting system to meet. It cannot meet them all.
Agreed, but it's hard to imagine an informed electorate giving up later-no-harm in preference to guaranteeing the election of the Condorcet candidate 100% of the time instead of 99.9% of the time.
I really would like to dispose of this ‘Condorcet criterion’ nonsense, once and for all (I hope).
If a system is devised that ensures that “everyone’s second choice candidate” (otherwise known as the Condorcet candidate, or winner) will be elected, then that system will enable the ‘later preferences cannot harm earlier preferences’ rule to be violated. If given an informed choice, most people would not want their lower choices to have an influence in an election while their first choice remains a contender.
In an election, the Condorcet candidate (if there is one) is the candidate who, when compared two by two with all other candidates, is preferred to each other candidate by more than half the voters. Whereas there would almost never be a candidate who was “everyone’s second choice”, there is often a Condorcet candidate, being a candidate who is preferred to all other candidates by a majority of voters. (All four Wellington mayoral elections under STV have seen the Condorcet candidate elected.)
At first glance, it may seem reasonable for people to want to discard an election method that does not elect the Condorcet candidate (if there is one), but consider the following highly artificial example where there are five candidates and votes—
101 AE.. 100 BE.. 99 CE.. 98 DE.. 10 E..
E is certainly the Condorcet candidate and, in spite of a poor showing on first preferences, really a very strong candidate in that if any one of A, B, C, or D were to withdraw before the count (for a single seat), E would win without question.
Can it really be said, though, that E deserves to win this election simply because he or she is “everyone’s second choice” - the Condorcet candidate? If we ignore the second preferences and treat this election as an FPP election, we would still not know that E was “everyone’s second choice”, and A would win with 101/408 votes (less than 25%). Being a PV election, however (in which E is excluded first), the winner would at least be elected with an absolute majority of the votes remaining in the election (101/201 votes).
What if this election were for four seats? Surely it would be absurd not to elect A, B, C and D. Regardless of how many seats there are, if the election method were such that second choices could be considered while the first choice was still a contender, possibly leading to the defeat of the first choice, then, as I said upthread, the voters would not indicate second and subsequent choices, and we would effectively be back to FPP again.
The question has to be asked, would voters want an election method that enables a candidate with as few as, say, 10% of first preference votes, to win an election because lower choices were able to assist a second candidate defeat a third candidate and the lower choices of the third candidate then helped the second candidate to defeat their first choice candidate? I would venture to say “No”.
Most Condorcet candidates are, in fact, generally popular candidates in that they will have attracted a range of preferences, including a healthy share of first preferences. This means they are not likely to be excluded early on, and therefore will remain in a position to receive many of the ‘second (and subsequent) choices’ of those other candidates that are excluded from the election. Most Condorcet candidates do, in fact, come through to win the election, although, as the above extreme example shows, it is not guaranteed, as you have pointed out.
In my view, it is really only in small, private, elections (or, of course, in artificially-constructed examples) that Condorcet candidates fail to be elected. In large, public, elections, they would almost always be the successful candidate. It really isn’t a problem, well except for public choice theorists (usually situated somewhere in US academia), and perhaps for Tim.
As you say, no election method is perfect, but M-PV and STV are far superior to the FPP systems most local authorities in New Zealand use; systems which make no effort to ensure, as STV does, that as many voters as possible are fairly and equally represented on their local councils.