How did the polls get it so wrong?

Discussion in 'General Discussion' started by TheNewNo2, 8 May 2015.

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  1. TheNewNo2

    TheNewNo2 Member

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    Leading up to the general election we just suffered, the polls were clear - neither Labour nor the Tories would be a majority, and while Tories would likely be a plurality their vote share was roughly the same as Labour. Judging by the current results, the Tories had a 6% advantage in the end result.

    This isn't the first election which the polls have got significantly wrong recently. Nate Silver points to three other recent ones: the US 2012 presidential (Obama underestimated by 3 points), US 2014 Senate (Republicans underestimated by 4 points) and the Israeli general election (Likud support significantly underestimated).

    While election polling will always be problematic, the fact that polls seem to uniformly say the same (wrong) thing is somewhat surprising, as each will have its own way of asking things and adjusting for the sample. So what's going on that all the polls are so wrong?
     
  2. jcollins

    jcollins Veteran Member

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    Polls are an estimate based on a representative sample. They'd be more accurate if we had proportional representation.

    In 2010 the polls expected a big increase in votes for the Lib Dems - which happened. However, the increase in votes caused Lib Dems to come second in a lot of areas where the Conservatives won which didn't do anything to increase the number of seats they had.
     
  3. crehld

    crehld Established Member Senior Fares Advisor

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    Polls are subject to a 95% confidence level and a 3 percentage point confidence interval.

    In lay man's terms this means the result of the opinion poll is expected to be correct 95% of the time; there is a 5% chance it won't be. When correct it is still subject to a 3 percentage point margin of error.

    The other problem with opinion polls is that our electoral system is not proportionate. So you have to model disproportional results based on a proportional sampling technique. One way to get around this would be to conduct opinion polls in every constituency, which would be much more accurate for a nation-wide picture but this isn't very practical from a pollster's point of view, and it is very resource intensive!
     
  4. Simon11

    Simon11 Member Jobs & Careers Assistant

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    or the fact that the people who voted for Labour in the polls, didn't actually bother to go in and vote.
     
  5. TBY-Paul

    TBY-Paul Member

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    The Majority of the Country don't want a Party from the extremes, Too far Left or Too far Right. The opinion polls were showing the possibility of the SNP having to much influence. So a lot of votes were switched to make sure that did'nt happen.

    The SNP being expected to win so big in Scotland made a big differance to how the Middle ground voted in England.

    Opinion Polls should be outlawed in the month leading up to an election, because they have such a negative influence on how people vote on the day,and PR introduced. It would remove tactical/negative voting.
     
  6. Yew

    Yew Established Member

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    Because we live in a country where less than 1/6th of the population counts as a 'majority'?
     
  7. telstarbox

    telstarbox Established Member

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    Why should opinion polls be banned and what's the difference between a poll and asking round your friends or colleagues?
     
  8. TBY-Paul

    TBY-Paul Member

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    Some Countries already ban opinion polls because of the negative effect they have on the final vote. It's one thing having a straw poll amongst your mates. It's a completely different matter having opinion polls published on a daily basis. All these individual polls plus Poll of Polls etc, being constantly published have got to have had some influence, otherwise they wouldn't be so wrong.
     
  9. telstarbox

    telstarbox Established Member

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    What do you mean by a 'negative effect?'
     
  10. TheNewNo2

    TheNewNo2 Member

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    I based my tactical voting on the 2010 result.
     
  11. bb21

    bb21 Moderator Staff Member Moderator

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    Is there any statistical evidence of the so-called "negative effect"?
     
  12. crehld

    crehld Established Member Senior Fares Advisor

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    The removal of opinion polls would not stop tactical voting. It is a psychological effect inherent with the mechanical design of single member plurality electoral systems (ie first-past-the-post). If you want to remove tactical voting you need to remove first past the post (which isn't going to happen anytime soon)

    --- old post above --- --- new post below ---
    I believe the phrase we might be looking for is "potential to influence the result of an election", of which some academic research exists. But the question of whether this influence is "negative" is subjective for which no impartial empirical evidence (on either side of the debate) could ever be presented.
    --- old post above --- --- new post below ---
    We don't know this, and neither do the opinion polls or the actual electoral result shed any light on the matter. That said expect to see some research conducted over the next few months about the motivations of voters.
     
    Last edited: 8 May 2015
  13. adrock1976

    adrock1976 Established Member

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    Another extraneous variable is that people may have misinterpreted the question asked, or they might not have answered truthfully, or might have changed their mind at the last minute.

    In peace

    Adam
     
  14. Paul Sidorczuk

    Paul Sidorczuk Veteran Member

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    Being of sound mind and still enjoying my very own cognitive ability to make a decision on the party that I chose to cast my vote in both General and in Local Elections, I take no heed of such polls.
     
  15. TBY-Paul

    TBY-Paul Member

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    I agree with everything you just said, only you put it better than me :oops:
     
  16. TheKnightWho

    TheKnightWho Established Member

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    The overall poll numbers have been bang on - 34%, 34%, 12% UKIP and 8% LibDem last I looked (may have changed since then), but the constituency polls were off.
     
  17. St Rollox

    St Rollox Member

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    The opinion polls didn't get it wrong in Scotland.
    They said labour would be wiped out and guess what, they were wiped out.
     
  18. Metrailway

    Metrailway Member

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    No that is wrong - the overall polls underestimated the Tories and overstated Labour significantly.

    The popular vote share is as follows:

    CON - 36.9%
    LAB - 30.5%
    LIB - 7.8%
    UKIP - 12.6%

    I suspect it is like 1992 again - the massive shy Tory factor and people making up their minds on the polling day itself.
     
  19. crehld

    crehld Established Member Senior Fares Advisor

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    Indeed, it's the translation from the overall proportion of votes cast to seats gained which is where opinion polls come apart. It's not the first time it's happened, nor will it be the last!
     
  20. Paul Sidorczuk

    Paul Sidorczuk Veteran Member

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    Call it what you like, that particular 1992 polls fiasco showed the fallibility of those who claim to be able to project matters forward in terms of possible results, whilst always making reference to the "uncertainty percentages" so applying....<(
     
  21. telstarbox

    telstarbox Established Member

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    Worth pointing out that the polls were very close to the actual result in 2010.
     
  22. crehld

    crehld Established Member Senior Fares Advisor

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    The polling companies are quite willing to admit fallibility. The problem is with the media who demand the polls to be undertaken and have become far to accustomed to using them to predict results and using it as the basis to inform the election debate. Past experiences, and indeed the polling organisations themselves, tell us they can be unreliable, yet those who commission them insist on treating them like gospel truth.
     
  23. Arctic Troll

    Arctic Troll Established Member

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    Opinion polls are already banned on the day of voting itself, because they are perceived to have a negative effect on voting behaviour. The exit polls cannot be published until voting has closed for the day, which is why you hear nothing until 10pm on election night.

    I'd agree about banning the publishing of opinion polls for at least seven days prior to voting. If they're a negative influence on election day, they're also a negative influence immediately prior to election day.

    As for the polls themselves, they were not that far out. The Tories got 2% more than expected, Labour 2% less, that's within the margin of error. The issue is that the these voting patterns were not uniform across the country. Labour's share of the vote rose in northern England, but as they were already secure there it didn't make the blindest bit of difference. Labour's share didn't rise in the marginals.

    Trying to apply a national swing to a marginal constituency is a difficult task at the best of times. I think this election was especially difficult.

    I think there are issues with "shy Tories"- Tories tend to be older, and tend to be less internet-savvy, so online polling (as YouGov predominantly use these days) doesn't show these people up. I also think Kellner made a good point in that some people in the marginals simply changed their mind on election day.
     
  24. Paul Sidorczuk

    Paul Sidorczuk Veteran Member

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    In the knowledge of such matters stated by you above, why do people with the ability to think for themselves without the so-called need to make reference to these polls, take any heed of how the media wish to utilise them. Have the media brainwashed a seemingly large and ever-growing percentage of the electorate into submission by their never-ending emphasis of electoral matters in the news programmes at the cost of actual news gathering of matters affecting the world, such as the disaster in Nepal, etc. It takes the trivial matter of a baby being born to a member of the British royal family to give a day's respite to the incessant self-effacing reportage of electoral matters.

    I mentioned upon another thread a few days ago of hearing a well-known so-called "media politico" say that he had never been so excited by a forthcoming General Election and I ventured the opinion that "he should get out more and get a life"...:roll:
     
  25. Arctic Troll

    Arctic Troll Established Member

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    I've seen this General Election described as "Eurovision for people who were picked last for games at school". It's probably fair comment.
     
  26. edwin_m

    edwin_m Veteran Member

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    Tactical voting is a symptom of people making a negative decision to keep out the candidate/party they like least, rather than a positive one to vote in the one they like most. I think this is inherent in our electoral system.

    The banning of opinion polls wouldn't help at all in my view. There would still be "Vote X - get Y" type comments by candidates, with the difference that voters would have less information to decide whether they were truthful.
     
  27. jcollins

    jcollins Veteran Member

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    Really no-one with a memory should have listened to the "Vote SNP and you'll get Ed Miliband" argument considering last time Cameron said "Vote Lib Dem and you'll get Gordon Brown" yet when some people did switch to Lib Dem they finished up with David Cameron when they would have been happier with a Labour-Lib Dem Coalition.
     
    Last edited: 8 May 2015
  28. Bertie the bus

    Bertie the bus Member

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    Which is irrelevant to the original question which concerned vote share, not number of parliamentary seats.

    I have no knowledge of the other results referred to but as far as this election is concerned I believe it was the polls themselves which caused the polls to be incorrect. The polls showed that Labour had no chance of forming a majority government and were very unlikely to even be the largest party. Therefore, for Labour to form a government they would have to have come to some arrangement with the SNP. My belief is that this prospect spooked enough English voters to vote Conservative when they possibly had no intention of doing so even a few days ago.
     
  29. jcollins

    jcollins Veteran Member

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    There was a suggestion on BBC News on Monday that the Lib Dems had in principal agreed to form a minority government in Coalition with Labour, subject to Labour and the Lib Dems getting more seats than the Conservatives, UKIP and DUP combined. It was also suggested the SNP would vote against a Conservative minority government but might back or abstain from voting if it was a Labour minority government.
     
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