Tuesday, 18 January 2011

Principles of AV/FPTP in real life

The Famous Fire Analogy

Two men are standing outside their respective houses.

Unfortunately for the two men their houses are on fire.
Each man has a wife, a beloved pet and a TV (they are minimalist).

Out of the two men, one of the man's wives, let call him Man 1, has already evacuated his wife. Man 2 on the other hand, hasn't.

Out of the two men, which one would you imagine is more prepared to charge into the flames?

Now, is it far to say that the newly introduced Man 3, who has got both his wife AND his pet out of the house is even more likely to charge in?

Transfer this over to the AV voting system.

Who has most support, someone voting for their first choice (wife) or someone voting for their second choice (pet) because their first choice is now out of the picture or someone voting for their third choice (wardrobe) because their first and second are out of the picture ?

Would it be accurate to Man 1 cares no more about charging the flames than Man 3 does? I don't think so and when the Fire Department turn up I know where any non bias person would send them first.

1st preferences count more than 2nd , 2nd count more than 3rd. Any system that does not recognise this, does not accurately measure support.


  1. "Who has most support, someone voting for their first choice (wife) or someone voting for their second choice (pet) because their first choice is now out of the picture or someone voting for their third choice (wardrobe) because their first and second are out of the picture ?"

    If you're doing a true comparison then each man cares enough to run in or not. If they run in then they're doing it because they care. If they don't run in it's because they don't care. It doesn't matter the degrees to which they care, only that they act or not.

  2. ...Lee, honestly? Are you trying to not get the points i make? Are you more likely to run in to save your wife or your wardrobe? It isn't a difficult question so it shouldn't take you too long to answer.

  3. The question isn't what I'm more likely to do, either way I run in or not. If my Wife is analogous to the Lib Dems, my pet to Labour and my wardrobe to Tories then I *care* enough to save the wife and my pet, but don't care enough to save my wardrobe.

    The question really is does man 2 care about his pet more than I care about my wife? I'd hope not...but maybe it's been a difficult relationship...maybe man 2 had his life saved by hit pet once and feels an enormous debt to it.

    You can downplay Man 2's second preference, his pet, but that doesn't stop him caring about it more than you care about your first preference. You can't measure that. No one can. No-one is SUPPOSED to.

    Election systems are binary, if you mark a preference it's because you want them or not, even if you have an order you'd prefer to like them to be considered in.

  4. The problem is your analogy is missing an important factor. The difficulty to rescue the item, which represents the likelihood of the candidate winning.

    If your wife is in there, she is a, an obvious first choice, but b, relatively easy to get out of the building.

    In a first past the post situation, your 'wife' would be a main party candidate with a reasonable chance of winning and also your first choice. I was lucky in the last general election in that the party I wanted to vote for was also the party I would have voted for if I had to vote tactically.

    However it's far more common, that the most important object to you is something incredibly difficult to rescue. Let's say you don't have any family or pets, just lots of precious valuable items, a grand piano, some valuable paintings and a TV.

    The grand piano is the most precious to you. There's no way you're going to get it out of a burning building though. If you have to make just one choice, ideally you'd choose the piano but you know you'd just die trying to get it out and save nothing (wasted vote). So instead you go for the paintings, (your second choice, reasonable chance of rescue).

  5. With AV, you rank the Piano 1st and the Paintings 2nd. Someone else, might have a wife and not a piano but they have paintings too. Chances are they care more about the wife than you do about the piano, but you both value the paintings the same, and paintings are both of your second choies.

    OR someone else might NOT have a wife or a piano, but have paintings. They will rescue the paintings and they will care just as much about their paintings as you do about yours, even though their paintings are their 1st choice and your paintings are your 2nd choice.

    This aims to show that preferences are NOT measures of absolute support. They are only measures of relative preference between the available options. Absolute support does not change with what's available. Relative preferences do change. So whether you put a candidate 1st or 4th is not an indication of how much you support them. Two voters could support a candidate the same amount as each other, but one happens to support a number of others even more so.

  6. Let's say there are two voters who like a candidate. They agree with each other completely on all of that candidate's policies and support the candidate just as much as each other. However it just happens that there's another candidate who has offered a really attractive sounding policy on immigration, and immigration is really important to one of the voters but not the other. So one voter gives a 1st preference, the other gives a 2nd, but both are equally supportive of the candidate.

    This is why it's fair to measure votes coming from different degrees of preference as equal, and why it would be completely unfair to add weightings to preferences, not least of all because it would bring back tactical voting.

  7. @Ben, we have spoken about this. how difficult it is to save is irrelevant as this is about how much you want to.

    Your support is not influenced by how likely they are to win. Your support happens.

    In your example, one person did not support the candidate the same as the other, as they would have both voted the same. To one the immigration policy on one made one candidate better than the other

  8. Lee, so you are honestly telling me hand on heart that you would not be swayed by WHAT you ahve to save? If your wife was in the house you are just as likely to run in the house as if the only thing worth saving was a wardrobe?

    Answer the qeustion

  9. I'm not saying that (and I haven't actually come anywhere near to saying that, not sure where you've picked up that misrepresentation)

    I'm saying the fact I run in or not is the only thing that matters. I either chose to run in or not. It's a fairly simple concept entirely analogous with voting in elections. I'm surprised you're not seeing it.

  10. It is not in anyway! please answer the question,
    Is the likelihood of you running into a building affected by what it is your are running in there to save?

    You wouldn't run in there for no reason so you claiming people do something or don't do something not based on personal motivation is a bit tiresome.

    Please answer the question.

  11. Yes, but whether I run in or not is all that matters. Shall I repeat this simple fact more for you until you understand? I'm trying to help you here, so you understand how to make an analogy work.

  12. BTW, me saying "I'm not saying that" is answering your question. If I am not saying "I would not be swayed by what I have to save" then, by logical conclusion, I am saying "I would be swayed by what I have to save".

  13. Actually I'm not sure how we make this analogy work, it's not even suited to single member constituency comparison...

  14. I'm afraid the difficulty has a huge impact. That's why FPTP encourages tactical voting and AV does not. How much a voter cares and what a voter actually does shouldn't be different, but with the wrong voting system they are. When the voting system makes you choose between acting on the postive or negative end of your views you're going to end up with your ballot not necessarily representing your positive support. Difficulty is an essential factor in this.

    And again you are confusing preference degrees with absolute levels of support.

    If I have a wife I'll choose her over a piano. If I have just a piano I'll choose the piano first. If someone else chooses their wife first and I choose my piano first does that mean we both care about our respective first choices the same amount? Of course not.

    Especially if I have a just a piano and someone else has a wife AND a piano. I care about my piano the same amount as he cares about HIS piano. It just happens that he cares about his wife EVEN MORE. Absolute support and degrees of preference are entirely separate and you can not infer one from the other.

  15. Finally,
    sorry i am not used to having to rely on double negatives to get yes no answers 'Do you want tea?' ' I'm not saying i DON'T want tea'...anyway

    You "I would be swayed by what I have to save".
    you "It doesn't matter the degrees to which they care" [they would run in the fire or not]

    These contradict eachother, but you are obviously clutching at straws not.

    If you care more about something you are more likely to run into a buring building to save it. This is what I am getting from you now and it is what makes sense.

    How much you care about running into the house depends on how much you like what is left in it.

    How much you support your preference depends on how high up your preferences they are.

  16. Ben, the difficulty does not matter.

    If i said do you like cake the answer would be the same whether the cake is 3 miles away or in my cupboard, you either like cake or not, how easier it is doesn't affect it.

    We need to move on from this point, so can wegree that how much you like something does not depend on availability.

  17. Ben, i am starting to get a feeling you are being disingenious. You are suggesting people would care about material things over their wife and using this as 'the norm'.

  18. Ok let's be clear here. Ballots don't show absolute support, they show relative preferences. Ballots are also influenced by difficulty. Support may not be but what you put on your ballot is. So you cannot derive support from the ballot.

    Yes I like cake just as much when it's three miles away as when it's on a plate in front of me. However will I go 3 miles to get it? Far less likely. How much I support/care about the cake stays the same, but my likelihood to go and get it is affected by the difficulty. Voting for something on a ballot is your likely to go and get it, not your absolute support.

    I am certainly not suggesting people care more about material things than their wife. I'm suggesting that having a wife and caring about her more than something else, doesn't change how much you care about something else. People don't have a finite amount of care/support that they divide among possible objects of affection. Does a mother who has twins only love each twin half as much as a similar mother who has just one child? No. Each of the three children gets the same amount of parental care.

  19. No, of course not children are children. How candidates are not candidates and they wouldn't be standing on the same platform.

    ...But surely under AV , support IS reflective of ballot...that is one of the main arguments in favour of AV that it allows people to vote freely without worrying about who MIGHT win.

    This was even a subject of a flow chart i seem to remember...hmm flow chart