Tag Archives: mlv

RCV vs MLV redux

Every time I think I’ve shown that ranked-choice voting is a step forward but no panacea, it appears again. Latest reply to a NakedCapitalism post below:

 

Ranked choice voting *sigh*. Don’t get me wrong: in choice between RCV vs FPTP (the status quo in most of USA and UK) and I go for RCV in a heartbeat, particularly since I have dual UK-Australian citizenship. However, there are people playing with fire here using arguments they don’t understand and if you’re interested in anecdotal evidence, those of us who spent decades eliciting public preferences in Australia came to despise the Conversation for its terrible editing etc which allows statements like, in the current article:

 

“Some critics incorrectly claim that ranked choice voting lets voters cast more than one ballot per person, when in fact each voter gets just one vote.”

 

 True but highly misleading and proponents will be in REAL trouble when the FPTP PMC class find the right “sound-bite” to counter this. Here’s one possibility: “RCV lets voters cast one vote but some votes are worth are a lot more than others”. My colleague Tony Marley couldn’t prove this was wrong in his PhD back in the 1960s and freaked. He ended up making a much milder statement. RCV (based on the rank ordered logit model) does NOT give everyone equal weight in the (log)likelihood function and this can matter hugely.

 

 South-West Norfolk is a UK Westminster Parliamentary constituency in which RCV would make ABSOLUTELY NO DIFFERENCE because the Conservatives practically always win it with way more than 50% of the primary vote – there would BE NO “second round” etc. The fact that at the last election a candidate for the Monster Raving Looney Party stood – something that only ever used to happen in the constituency of the sitting Prime Minister as a publicity stunt – shows that anger in the general population is spreading.

 

 Statements above in this thread have been that RCV can lead to “communism” or “mediocrities”. True but not the experience in Australia. In fact it simply allowed “non-mainstream” people on both sides to gain a few seats but the broad split in terms of “left and right” was replicated in Parliament. Sounds good? Hmm. Statement of (non) conflict of interest. I am one of 3 world experts in a way of eliciting public preferences called Best-Worst Scaling. Dutch/Belgian groups applied it (with NO input/knowledge from me) to voting to give “Most-Least Voting”. A “scaled back” version of RCV in which you ONLY indicate “top” and “bottom” candidate/party. This is because people are lousy at “middle rankings”. I once hypothesised a scenario as to where RCV could give a seriously problematic result which MLV might avoid. To be honest I considered it a theoretical curiosity. Until it happened in the Iowa 2016 Democrat Primary. Essentially there was a dead heat (approx 49.75% each) for Sanders and Hillary. O’Malley came a distant third with 0.5%.

 

 RCV would have essentially given 0.5% of voters in a single state the decision as to who won and got the crucial “momentum” that might have made them unstoppable. MLV would probably have gone as follows: Sanders supporters put him as most desired and Hillary as least (49.75-49.75=0% net score). Vice versa for Hillary. O’Malley gets 0.5%; which of Sanders/Hillary is “last” depends on whatever O’Malley’s supporters think is the “worst evil”. I don’t know who they’d have chosen. But it doesn’t matter. He’d have won.

 

 Many will say “for the last placed first-voted individual to win is a travesty”. I’d reply “why is this any less of a travesty than 0.5% of Iowa Democrats potentially deciding who faces Trump?” Depends how you phrase it. Arrow’s Impossibility Theorem all over again. Effectively Iowa was a tie in which neither Sanders nor Hillary “deserved” a win. It should have caused the “race” to move on. Instead O’Malley dropped out. You see how the SAME votes can lead to VERY different results depending on the system (likelihood function)? After all, MLV with 3 candidates *IS* RCV! At least in the “ranking” you give. But the AGGREGATION and WEIGHTING is different.

 

 Final note – for those who think I’m plugging something “I devised” – you haven’t read the post. I WISH I’d been involved with voting theory. But it’s one area I had NOTHING to do with using BWS. I admire the Dutch and Belgians for applying it this way and it has, in fact, been used in Baltic States. So it ain’t some weird theoretical curiosity. Ironically it MIGHT lead to some centrist “mediocrities”. But given Hillary and Trump, maybe that might not have been so bad?

 

 RCV is a step forward. But be careful what you wish for. Personally I think that redistricting to eliminate uncompetitive seats (gerrymandering) and other aspects of electoral reform are at least as important as changing the voting system. I’ve given the references before on here and elsewhere. Happy to engage in constructive discussion since NO voting system is fair.

 

 

Most_least Voting(2)

Most-Least Voting – Questions raised – some of which were serious, some I suspect were “rabble-rousing”. I’ve edited to reduce snark and generally tried to give benefit of the doubt, even though I know some people really should just go out more……

Arrow’s Theorem only applies to generic voting. Fair results can be obtained if particulars are taken into account. When you only have a few candidates MLV is not what you’d go for. With a huge pool of eligible candidates, say 1000, all available for say 9 seats, then Cumulative vote tallying is ideal.

Reference please.

“Also something polsci experts often fail to consider is degree of polarization. You don’t have to have just “like” vs “dislike”, you can have a Likert scale on degree of like/dislike, and use it to weight the votes, so that a polarizing candidate who is less polarizing than the other still has a chance to be ahead of the milquetoast centrist. I know, I know, requires fairly sophisticated voters, but worth a shot some time in experimental research trials.”

Likert scaling assumes distances between each choice (answer option) are equal. Please provide references from the mathematical psychology literature showing this to be true. (I’ll save you time – there are none. My co-author was editor of the top journal –JMP – for almost 40 years and never encountered a study showing this. He is AAJ Marley.).  I could quote you amusing anecdotes like the fact traditional Chinese older people associate the character for number 4 with death so avoid it. Statisticians then spend yonks trying to work out if dips at number 4 are “real” or “due to cultural stuff”.  Please stop throwing up new terms like “likert” when it is merely expressing a phenomenon I discredited in my postings before.

San Francisco city government, supervisors, sheriff and district attorney are chosen by ranked choice voting. That, combined with district elections for supervisors, has resulted in a parade of ineffectual, sometimes dangerous, political mediocrities, a chaotic disaster, controlled by the Democratic County Central Committee. If a voter fails to choose three candidates, their vote is thrown out.

You say ranked choice choice voting – I’m not defending that – so your point is?

Some supervisors have been elected with less than 25% of the vote.

Choose from Hillary, Trump and any run of the mill US politician in the centre. Why does LESS THAN 25% “MEAN THEY ARE ILLEGITIMATE”?  – “Top” candidatees don’t matter under MLV if they also disgust a huge number of the rest of the population. This is NOT ranked voting (which YOU talk about). Please actually address my discussed voting system and don’t straw man.

It’s horses for course to get around Arrow. In other words, you select the most appropriate voting system for the size of the candidate pool and the seats being vied for.

I said your latter statement at the start. Why are you presenting this as a “new insight”? Arrow always said you make your moral judgments, based on “values” and the “system”, THEN you can choose the system that best achieves these. As to “get around Arrow”. Nope.

While it is an interesting fad, there is no real guarantee that rigging elections to favor centrists will get you better government. As it happens, I am a Libertarian. Some of my ill-advised fellow party members argue vociferously for ranked choice voting or the like. I attempt to point out to them that RCV tends to guarantee that my party will never win elections, but the RCV faithful will not listen.

Where did I say that MLV rigs elections in favour of centrists? I merely quoted an observation from the Dutch/Belgian researchers that centrists probably stand a better chance of being elected. If you have data showing that MLV disproportionately benefits centrists at the expense of others please quote it – PARTICULARLY in a multidimensional format (which even the continental Euroepan authors do not). Note I also said that in a MULTI-DIMENSIONAL world, the concept of a “centrist” is less meaningful. MLV could get you your libertarianism (in getting govt out of the bedroom). Please stop putting words into my mouth.

There’s a lot of talk about candidates and parties, but not a lot of talk about policy.

One way to create significant momentum to deal with global climate change is to place high taxes onto fossil fuels. As Illinois recently demonstrated, this is highly unpopular.

In either Ranked Choice or Most-Least systems, how do necessary but unpopular policies get enacted?

I’m not going to claim miracles. Just as under ANY other voting scheme, there must be a critical mass of people who “see the peril” and vote accordingly. MLV at least allows these people to “veto” candidates who totally dismiss the environmental issues. So it isn’t “the solution” but it may be “ a quicker solution.” One big benefit of MLV is that it is probably the system that gives the greatest “veto power” to any majority of the population whose candidate(s) didn’t make it into government. So in the UK, the strong environmental lobby crossing all the “progressive parties” who keep losing elections could start exercising real power via their “least” votes.

Ranked choice and most-least voting

I recently realised that two systems proposed as “PR-lite” or “a step towards full PR” can produce radically different outcomes IN REALITY and not just as a THEORETICAL CURIOSITY. The two are “single candidate ranked choice” and “most-least voting – MLV”, most notably when there are just three candidates.

Here’s the deal. Under ranked choice you must rank all three candidates, 1, 2 & 3 (most preferred to least preferred). Under most-least voting you indicate only the “most preferred” (rank 1) and least preferred (with 3 candidates, rank 3). The OBSERVED set of data should be the same. (I’m not going to get into the issue of why they might not – that gets into complex mathematics and I’ll do it another time).

For those who don’t want to get bogged down in the following discussion of the maths, here’s why the two systems can, given EXACTLY the same observed count data, give a different “winning candidate”. Ranked voting essentially tries to identify the (first or second best) candidate that the people-supporting-the-losing-3rd-party-candidate are “most happy with”. Under MLV, if both “first” and “second” preference candidates are diametrically opposite (and mutually hated) then NEITHER should necessarily be elected. The candidate who came a (very very) distant third can be elected if (s)he is NOT HATED by anyone. Essentially, if you polarise the electorate you are penalised. A “centrist” who hasn’t either “enthused” or “repelled” anyone will win under MLV.

I tended to think this was a “theoretical curiousity”. However, upon looking more closely at the 2016 Iowa Democratic Presidential primary I realised this ACTUALLY HAPPENED. Bernie Sanders and Hillary Clinton were essentially tied on about 49.5% each in terms of their “primary first preference vote”. Hillary had the edge, and the 3rd candidate, O’Malley dropped out (but too late so he got votes). Yet he was actually the key influencer, if either ranked voting or MLV had been used. Under ranked choice, either Hillary or Bernie would have won (determined by who the majority of O’Malley’s supporters put as second preference). Under MLV, and assuming that the “much talked about antipathy between Bernie and Hillary was real” then each candidate’s supporters would have put the other as “least preferred”. The “most-minus-least” counts would have been slightly negative for one and likely both candidates. O’Malley, on the other hand, would have obtained a small positive net most-minus-least vote (getting 1 to 2% of the vote, with few/no people putting him as “least preferred”). MLV simply subtracts the “least preferred” total from the “most preferred” total for each candidate giving a “net support rating”.

Under ranked choice voting either Hillary or Bernie would have won. Under MLV both would have been denied the win in favour of O’Malley, because he “pissed nobody off”.

Here’s the more detailed discussion.

Most-Least Voting (MLV) is a special case of a more general method of “stated preferences” called Best-Worst Scaling (BWS). Declaration of interest: I am a co-author on the definitive CUP textbook on BWS, was involved (along with its inventor) in much of the theoretical development and application in various fields (most notably health). HOWEVER I have had no involvement with the theory, parameterisation or application of MLV. Indeed, once I became aware of this method of voting, on checking the bibliography, it became clear that the authors were not actually aware of BWS and due to the “silo effect” in academia, had come up with it largely independently of what we had already done. Incidentally some of the Baltic States have used or do use MLV in certain instances so it isn’t just a “theoretical curiosity”.

OK, having got that out the way, what do I think of MLV? In short, I think it is worthy of serious consideration and wish we’d thought of it first! Like ranked choice voting with single member constituencies (something in use or proposed in various Anglo-Saxon countries like Australia, the UK and USA), it is not “proper” Proportional Representation (PR). However, it can be considered either as a nice compromise, or as a stepping stone to “full PR”. In terms of its similarities to ranked choice voting: suppose there are 5 candidates in your constituency. Under ranked choice, for the maths to not be horribly skewed and potentially very very gameable, you should be forced to rank all five, 1,2,3,4,5. The problem, known since the mid 1960s, is that people are good at “top” and “bottom” ranks but get very “random” and arbitrary “in the middle”. MLV exploits this. It only asks for top and bottom. Thus it may be considered to be the “minimum change to first-past-the-post – FPTP – possible” so as to “make things easy for people”. You only provide ONE extra piece of information – the candidate/Party you like least. If you do not provide both a MOST and a LEAST choice then your ballot is spoilt. This is IMPERATIVE for the maths to work, and for the system to be demonstrably “equitable”. (Most-minus-least vote totals must sum to zero.)

The common question is “Suppose there are only three candidates – aren’t ranked choice and MLV the same?” NO. See above for a real life example. Ranked choice MIGHT be unconstitutional in certain countries (if the mathematicians and lawyers got together because not everyone has the “same influence” mathematically).

So what is happening in practice?  The authors conclude that if the “FPTP winning” candidate espouses (say) a very extreme policy on (say) immigration or something, that all other parties abhor, then (s)he is likely to lose. All other parties “gang up” and place that candidate as “least”. Most-minus-least vote tally is net (highly?) negative. A more “moderate” candidate likely wins. Indeed, the authors claim that “centrists” likely prevail a lot of the time – though they might be an “O’Malley with 1% primary vote”. Though if a candidate would get a MAJORITY (and not just a PLURALITY) under FPTP, they’ll still win under MLV. So “majority” (non-coalition) governments still can happen – they’re just harder to achieve and “third parties” (etc) much more easily get a foothold. I happen to think that this “centrists rule” conclusion is a little simplistic when you move from a single dimension (left/right) to multidimensional space. Yes, maybe you get a candidate closest to the centroid across all dimensions but “how strongly people regard each dimension” can affect results. So, as they frustratingly say in academic papers, it’s “an empirical issue” as to what will happen. However, I will venture a conclusion that “extremists” will naturally get weeded out. Whilst some extremists might be generally considered bad (consider dictators who were first voted in via pluralities in 1930s Europe), others (painted as “extremists” by the MSM like a Sanders today or an Attlee or FDR of yesteryear) could be considered necessary and without them society would be much worse off. It gets necessarily subjective here…!

TL;DR: Arrow’s Impossibility Theorem still holds. MLV doesn’t solve all problems but it is attractive in addressing a lot of the most commonly made criticisms of voting systems used in the UK and USA. However, it isn’t the ONLY system that can address these criticisms – it is merely the “simplest” in terms of practicality and requiring “minimum extra effort by voters beyond what they do now”. Whether you “like it” depends on your “values”.