Earlier this week some eyebrows were raised over an article by Dan Hodges which quotes a “Tory analyst” saying he re-ran Lord Ashcroft’s poll of ultra-marginal Conservative seats and claiming “We reran it in the seats we hold […] but included the name of the sitting MP. We were ahead by 2 per cent” as evidence of the Conservative party’s belief in the power of incumbency.

Now, I’ve written about political parties’ private polls and the strange mystique they seem to hold over the commentariat here before. Essentially, if you see media claims that party’s private polling shows some wonderful picture that contrasts with the public polling it’s best ignored unless they actually cough up some numbers and tables so you can see what they are up to. Your response should always be “give us the tables or they don’t exist”. Part of the British Polling Council’s disclosure rules were intended to stamp out this sort of thing: if a poll is published, the company that did it must release the figures. It does, however, only apply to companies that are members of the British Polling Council – if parties use companies like CrosbyTextor or GreenbergQuinlanRosner then even if their numbers are leaked, the companies wouldn’t be obliged to release numbers. Lord Ashcroft here writes about it being a bad sign if the Tories are resorting to comfort polling, but I think that’s rather off the mark. Back in the day the then Tory Chairman Lord Saatchi himself used to come out with dubious morale boosting figures, this is a reference from an unnamed “Tory analyst” – I suspect, like Andrew Cooper suggests here that Dan’s source was exaggerating or doesn’t know what they are talking about.

But putting the mystery “private polling” aside, what about the substantive issue, what about the incumbency effect? This is supposedly the bonus that sitting MPs get – the benefit they’ll have from people who aren’t voting for the party they represent, but because of name recognition, or because people think the MP is hard working or decent, or helped the voter with a problem they contacted them with, what is sometimes called the “personal vote”.

Let’s start with Ashcroft’s August poll. In contrast to the implications of what Dan’s source said, Ashcroft’s poll already included an attempt to get at the incumbency factor. Rather than just asking straight voting intention, it double-asked the question, first using the normal poll wording, and then asking people to think specifically about their own constituency and the candidates standing there. The intention of this – something I first came up with for a PoliticsHome poll of marginal seats back in 2008 – is to try and get at tactical considerations and personal votes. The idea is that some people may not give their *actual* voting intention in the main question, they’ll give the party they support nationally, even if at a local level they might vote tactically or might vote for the local MP they like.

This approach appears to work – or at least, some people do give different answers, especially in seats where the Liberal Democrats are players. In Con-LD seats Ashcroft found standard voting intentions of CON 33%, LAB 24%, LDEM 18%, UKIP 14%, but when he prompted to get people to think about their own constituency it became CON 32%, LAB 18%, LDEM 29%, UKIP 12%. That the difference is concentrated in Lib Dem seats does imply that it is picking up people’s tactical voting considerations, and perhaps personal vote considerations (Ashcroft wasn’t polling Lib Dem held seats, so he obviously wasn’t, but I’ve done the same in Lib Dem held seats in the past and the two-question approach makes a huge difference). In Ashcroft’s August poll in Con-Lab marginals though the two stage question did not produce any drop in Labour’s lead in the second, more “locally prompted” question. No sign of an incumbency vote there.

By definition, any incumbency bonus should be the most obvious in seats with new incumbents. In seats where the MP was already there at the previous election any personal vote should already be taken into account, in a seat with a new incumbent any personal vote should be above and beyond what the party got last time, so if there was an incumbency effect we would expect to see a party doing better than average in seats with new incumbents like the ones Ashcroft polled. Again, this was not the case – in Ashcroft’s August poll the swing to Labour was about 2 points higher in the marginals than the GB polls at the time were showing.

That bit of evidence seems clear then. The problem is, the incumbency effect is not a vague theory, the evidence for it happening at past elections is pretty damn solid. In 2010 Labour lost an additional 2.2 percentage points in seats where an incumbent MP stood down compared to seats where the incumbent contested the seat. The Conservatives vote rose by 2.9 percentage points in seats where an incumbent stood down and they lost the incumbency effect. In seats with an existing incumbent it rose by 3.8%, in seats with a new incumbent first elected in 2005 the Conservatives increased their vote by 5.6%. The same happened in 2005, the Conservatives did 1% worse where an MP retired, 2.5% better where there was a new incumbent.

Going further back the record is more patchy (while the Conservatives did worse where MPs stood down in 1997 and 2001, they didn’t do better in seats with new incumbents), but there is a strong and consistent effect in elections following on from an election where a party gained many seats. It is even clearer in the seats that a party gained at the previous election (the so-called double incumbency bonus), so in 2010 Conservative MPs who gained seats from opposing parties in 2005 did 1.9% better than average, in 2001 Labour MPs who gained their seats in the 1997 landslide did 2% better, in 1997 Labour MPs who gained a seat in 1993 got a bonus of 4.3%, in 1992 Labour candidates who gained seats in 1987 got a bonus of 2.7%, in 1987 Conservatives who gained seats in 1983 enjoyed an extra boost of 3.9%. For Liberal Democrats, incidentally, the figures are even bigger. (*)

There is no reason to think the same will not happen next time. New incumbent MPs will do better than average, seats where an MP retires will see the party of the retiring MP do worse. It will affect all parties, but because most of the battleground seats between Labour and the Conservatives are ones with new incumbent Conservative MPs who gained the seat in 2010, on this occassion it will favour the Conservatives.

If that is the case though, why didn’t the Ashcroft polling pick it up?

Well, there are a couple of potential reasons. One is obviously that the incumbent effect has vanished for some reason. Personally I think this unlikely – the general trend has been for MPs to devote ever more of their time to constituency matters and their “social worker” type role – but it is certainly possible. Alternatively it could be that it’s there, but that the polls don’t pick it up. Perhaps such things don’t really emerge until the election campaign itself, or perhaps the big differences the “two-stage question” approach produces in Lib Dem seats are just tactical considerations and there isn’t really a good way we can get at incumbency effects. Alternatively, you need to remember that the August Ashcroft poll is just one poll – the previous Ashcroft poll of marginal seats in January 2013 (the bigger one that did lots of different groups of marginal seats) did actually show a very small pro-Conservative incumbent effect from the two-stage question in Con-Lab seats, and did show the Conservatives doing slightly better in the marginals they were defending than in the country as a whole, the patten we would expect to find given the past history of incumbency effects.

And that brings us back to the original question and the orginal polling that whoever was talking to Dan thought they had seen. If there is an incumbency effect, then on past experience it will be a couple of percentage points. If asking a question a different way changes a 14 point deficit into a 2 point lead, then that’s not an incumbency effect, that’s a shonky question.(**)

I expect there to be an incumbency effect, but it’s going to make a couple of points of difference, not 16 points. It’s one of the reasons I think the Conservatives could probably get a majority with a 7 or 8 point lead rather than 11 point lead they need on paper, why the Labour party need a slightly bigger lead than what a uniform swing suggests. It’ll be a small effect at the margins though, not something that transforms the election. It makes the election a bit harder for Labour to win than uniform swing suggests, but not much. It makes seats a little easier for the Conservatives to defend, but they still have a mountain to climb.

(*) The 2010 figures are from Curtice, Ford and Fisher in Cowley & Kavanagh’s British General Election 2010, the figures for 1983 to 2005 are from a research note by Tim Hallam Smith here, alas behind an expensive academic paywall.

(**) At least, it is with a Tory 14 point deficit. As we’ve seen from the two-stage questions above, in Lib Dem seats it’s a bit of a different story, but that will be tactical considerations as well as incumbency

150 Responses to “On Private polling and incumbency effects”

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  1. EL

    Whatever gave you the idea that *I* did any of that which I was recommending? The idea!

    Actually I kind of did, once, but only when I did it for myself to become a councillor (it’s not really worth it, to put it mildly, unless you have a specific goal. Libdemmery wasn’t mine).

  2. Turnout of 80.3% looks on the high side for St Ives in the 1992 general election.

    Allegations of Granny farming, or the Tipp-Ex trick there.

    There were concerns in other constituencies, but I seem to remember a number of investigations were delayed for just over one year. The ballot papers were destoyed after a year-and-a-day I believe.

    Nick Davies writes of 1992 that ” …the entire national result was decided by only 1,241 votes distributed through 11 key marginals.”


  3. John Pilgrim
    Thanks and i have great respect for Tony Dean’s experience.

    I still think you can’t overcome UNS and in fact he concludes that too, essentially, on his LD /Con situations. However, this time LD is in coalition and one has to contend with the fact that hell hath no fury like LizH’s feelings of betrayal.

  4. Very much looking forward to Desert Island Discs tomorrow,because music tells us so much about a person.I hope he just goes for what he like but if he
    Does not I reckon “Great balls of fire”could be quite amusing.Actually a great
    Song by a great performer.


  6. @ Roger Mexico I suspect automod does not like length (or is at least more likely to have a look at long posts), S/he is not obviously biased. I began my last post with fulsome praise of AW himself but it was still detained by his servant.

  7. Charles

    My comment actually contained a long quote from Mr Wells himself! Actually that might be the problem as his posts aren’t subject to automod. Of course the reality is that the longer a comment is, the more likely it is that a random concatenation of letters will tickle automod’s fancy and send it to Purgatory. Anthony’s usually quicker to sort them out, but I suppose he’s got something better to do.

  8. Howard
    You still have that Golden glow despite losing the background colour, I too never worked quite as hard as when I was seeking to get myself elected !

  9. Will there be any polling in regard to whether Dominic Grieve should resign, following unwise comments he had made, which some have branded offensive ?

    Always difficult for pollsters to raise questions on specific stories in the media, particularly when they touch on race relations.

  10. Quite a fierce editorial by Ed Miliband in the Indy on Sunday tomorrow. https://pbs.twimg.com/media/BZyEPd-CQAAicYk.jpg:large

    “His main political strategy is now to sling as much mud as possible in the hope that some of it sticks. When he does so, he demeans his office.”

    Not going into my personal feelings on what he says, but it’s rare that we see such a strident attack from a leader of the opposition.

    We’ve seen “Angry Ed” before of course, during the Daily Mail affair, but this is a generalised attack rather than a response to one issue.

    Curious. The rhetoric seems to be escalating well in advance of the GE.

  11. No Tweet from the Sun,
    Then that ‘s a good ‘un !

    (For Labour that is).

  12. @ Ewen

    That’s because tomorrows poll is for the Sunday Times and they are always released at 6am.

  13. Bet if it was really really good for the Blues the Sun would snitch it.

    Although they have to be on their best behaviour now of course.

  14. @Roger Mexico In theory, you could test whether it was length per se or the greater probability of noxious content in long posts, Just send one long post and then each paragraph in it separately. Problem is that you would have to do this many times and would probably be placed in permanent automod as a result. Anyway hope you come out soon. I almost always find your posts highly enlightening.

  15. Prediction time: lab 40 con 31 lib 10 Ukip 12

  16. Lab 38
    Con 36
    Lib 9
    UKIP 9

  17. Billy Bob
    There was a thriller written called ‘Game Ten ‘ if I remember correctly , which was based ,pretty much,on what you wrote, and that the 92 election was stolen. I think Gerald Seymour might have been the author.

  18. It was by James Long – I just Googled it.

  19. Fair enough, as I recall the stats the plot was based upon did seem robust and the extrapolation from them was plausible. The Graun got quite excited about the issue for a while, I seem to remember.

  20. Surely you are simply putting down the figures you would like to see and fits your Political views
    So it follows that I may as well put:
    Con 36
    Lab. 37
    LD. 10
    UKIP. 8

  21. @Ewen Lightfoot, Mr Nameless

    Thanks for that.

    “TV reporter, Claire Merrick, fronts National TV’s crime show. The survivor of a previous scandal, she discovers irrefutable evidence of election rigging and that someone is out to destroy her credibility again. The world’s most powerful and secret club is at work, and Claire goes on the run.”

    Copies of the 1995 edition available from second-hand book retailers.

  22. Sine Nomine,

    As a not-very-well-concealed lefty, I think predicting a 2-point Labour lead makes me quite the pessimist.

  23. sine

    “Surely you are simply putting down the figures you would like to see and fits your Political views
    So it follows that I may as well put: ……. etc etc ”

    For all the significance you might as well put anything.

    I think we can safely say Chris’s will be closer though.

  24. Sine Nomine – It shows that the Conserfvative Party must be is a bit of a pickle when your preferred poll still shows Labour ahead.

    My unbiased prediction:

    Labour 41%
    Cons 31%
    Ukip 12%
    Clegg 9%

    However Dan Hodges has been told from a Tory insider it is:

    Labour 18%
    Cons 61%
    Clegg 13%
    Ukip 4%

  25. I must have missed the foundation of the Clegg Party!

  26. From Sir Nick Harvey Lib Dem MP for North Devon “Stand fast a game changing event, which is always possible in the febrile political era in which we live, Labour is on course to win the next election,” he declares. “This election is Labour’s to lose.”

    Err……I agree with Nick!

  27. I was not far off for tonight Yougov

    Lab – 40%

    Cons – 33%

    Ukip – 11%

    Clegg – 9%

  28. I think we have a new polldrums.

    Seriously though, that’s a fairly solid 40 Labour find themselves on recently. I do wonder why the VI graph seems much less volatile than previous parliaments.

  29. red rag

    Not far off what?

  30. MR Nameless – I just think those Lib Dems who switched to Labour three and a half years ago are now that set in their ways and determined in voting for them, that nothing will budge them. It wont help the Lib Dem cause that they have David Laws writing their manifesto. The ultimate own goal. As one Tory MP said not long ago “he is more right wing than many in my party”.

  31. I think Labour will be very happy with the regular 40% but will the Labour Finances issue hit pre or post 2015 ? … and if pre what effect would it have to the GE.

  32. Marco
    Could you be specific re the Labour ‘finances issue ‘ please?

  33. From Sir Nick Harvey Lib Dem MP for North Devon “Stand fast a game changing event, which is always possible in the febrile political era in which we live, Labour is on course to win the next election,” he declares. “This election is Labour’s to lose.”

    Like Red Rag I think that is about right at the moment.

    Still the 2014 euroelections and referendum on Scottish independence first.

    I suppose a future UK (or however renamed) without Scotland would be less favourable to Labour?

  34. Pretty close to my prediction @sine

  35. Interesting responses to the Coop questions in the poll this morning.

    They were asked:

    From what you have read or heard about this
    story, who do you think is most to blame for the
    original appointment of Reverend Flowers as
    the Chairman of Co-op bank?

    Respondants from all parties gave most blame to the Coop board vs Politicians in the Coop movement:

    Party – Board – Politicians

    Con – 50 – 25
    Lab – 47 – 9
    LD – 53 – 14
    UKIP – 41 – 22

    Do you think George Osborne is right or wrong
    to order an independent inquiry into how
    Reverend Flowers was appointed Chairman of
    the Co-op bank?

    Party – Right to order enquiry – Wrong to order enquiry

    Con – 79 – 12
    Lab – 62 – 24
    LD – 73 – 20
    UKIP – 73 – 17

    Again, a similar response across the board.

    Next a question decidedly more partisan:

    Currently the Co-operative Group (the parent
    company of the Co-op bank) is a donor to the
    Labour party and the Co-op Bank provides a
    large overdraft to the Labour party. Many
    Labour MPs stand as joint candidates between
    the Labour party and the Co-operative party.
    Do you think the Co-op should continue to fund
    and work with the Labour party, or should they
    break their links?

    Party – Coop fund/work with Lab – Coop not fund/work with Lab

    Con – 9 – 79
    Lab – 61 – 17
    LD – 31 – 49
    UKIP – 11 – 74

    Really polarising data.

    So the line taken by David Cameron over this could have carried broad consensus by sticking to an independent enquiry about the appointment of Mr Flowers.

    However, by pushing the Labour connections and funding he has gone into a totally partisan area that is devisive, and in my view shows party politics in it’s worst light.

  36. @Catmanjeff

    You only have to read the DT to see that many on the Right are very uncomfortable with the way the Govt have taken a partisan line on the Co-Op (and it doesn’t seem to be the PM who has come up with it, but the Chancellor), and about how they seem to be suggesting that funding the Labour Party is a sufficient sin to be attacked in Press and Parliament.

    There are some in the Tories who seem to see their solution to unelectability to be to try to give the electorate nobody else to vote for. But as strategy goes, it’s foolish.
    I think the chances are now very high that an incoming Labour Government will return the complement by passing legislation making most Tory funding illegal by limiting individual and corporate donations, and were that to happen, certain senior Tories would have only themselves to blame.

  37. @Chris Riley

    Thanks for that. I will look up the DT later.

    I’ve heard this before about ‘depressing the electorate’. I hope that at the next GE at least one party offers an unambiguous positive manifesto and campaign, with no personal attacks or smears.

  38. @Catmanjeff.

    Unfortunately I think that third “question” confuses the issue by actually being two completely different questions rolled into one.

    It is perfectly possible to think that the CoOp should stop donating to the Labour Party (as I am quite sure you think that JCB should stop donating to the Tory) party without believing that the CoOp is wrong to provide an overdraft to the Labour Party. I am sure the answers to the two, distinct, questions would show a similar polarity to the first one but probably much more consensus on the second.

    As it happens, the change of ownership of the CoOp Bank seems to be leading to a reduction in its support for Labour anyway.

    Personally I would support, in principle, state funding for parties linked to donation limits, but I worry that in practice it would be impossible to police this as we would simply see a proliferation of US-style “political action committees” spending money on indirect political campaigning. I think this would be particularly a problem with the Unions and with Big Business, each of which would pump money into attack ads aimed at the Tories and Labour respectively.

    If we could find a law nuanced enough to curtail that in practice (easy enough to write one that says you can’t do it in theory) then I would be all for a ban,

    I would link state funding to votes cast in previous elections by the way, with a pro-rata “bounty” attached to each vote cast in different types of elections. Say £1 for Westminster votes – with a 20p bonus for votes in England to compensate for lack of devolution – 30p for devolved votes, 20p for Euro parliament votes and 5p for local authority votes. Apart from anything else this would give people a reason to vote even in areas where their party stood no chance, so might improve turnout.

    You’d hake to greatly improve measures to reduce voting fraud though, as it would create massive incentives for activists to stuff ballot boxes.

  39. @Neil A

    I think that all large corporate donations to any party is not good.

    I agree with state-funding. It has problems, but it’s better than the murky world of large donations from individuals or organisations.

  40. EM is in the Independent today really laying into DC on the co-op ‘smears’ and Yvette Cooper has been very aggressive on the subject on Marr. There is a concerted effort on Twitter by Lab supporters and MPs.

    So Lab are not taking the co-op situation lying down.

    I am again impressed with EM for taking this on so vigorously. In the article he compares the co-op smear to the smearing of his Dad v clever.

    It seems the Tories are out to try to destroy the trade union and the co-op movements and at these times of austerity I am not sure it is going to have the resonance they want.

  41. catmanjeff

    “@Neil A

    I think that all large corporate donations to any party is not good.

    I agree with state-funding. It has problems, but it’s better than the murky world of large donations from individuals or organisations. ”

    I totally agree with this. As I said in a comment yesterday, there could be state funding as a top up to subscriptions. I would cap donations from one person or organisation to no more than £5k per year. I would stop the parties obtaining large loans as well. We need to restrict how much is spent on politics, so we don’t go down the road of having as much political advertising as the US.

  42. @R Huckle,

    But there you have the dilemma. The US already has a lot of those rules, and PACs are used to get around them.

    If we’re going to do it we need to be cleverer. More clever than I suspect we’re capable of being.

  43. @Couper,

    If, as I suspect, the purpose of “Operation Flow-ers” for the Tories is simply to cement in the mind of the electorate the link between Labour and banking, and between Labour and sleaze, then “not taking it lying down” may actually play into CCHQ’s hands.

    If Labour spokesmen repeatedly say “The PM is smearing us by linking us to disgraced banker Paul Flow-ers” then it may be that all the public, listening with their usual half-an-ear, will hear is “Labour…. disgraced… banker”.

  44. @Neil A

    Exactly in general if you are not going to win on an issue you shut up about it. So Lab obviously think it is either a winning issue or that it is so dangerous it can’t be ignored.

    They may have decided that a negative election is dangerous. So the association they are building is Tories = Smears so the public will discount the negative Tory messages come the GE.

    They did it successfully with EM’s Dad and the Tory Press where now I think Red Ed as an attack is very blunted and I think they are doing the same thing here with the co-op so any sleaze attacks will be blunted.

  45. If the aim of “Operation Flowers” is as Neil suggests, it’s the type of politics I would hope is widely rejected by the electorate.

    Any party using negative smear by association exacerbates the low turnout and low trust problems that blights modern party politics.

  46. Surprisingly good Desert Island Discs appearance from Ed.

    Seemed to bring across some genuine emotion when talking about the Red Sox, Justine and his dad.

  47. I’m sure lots of us ladies were listening to Ed on Desert I Discs. Lucky Mrs Ed!

  48. If EM did well on DID then it’s just a pity that hardly anyone listens to it. We have the Home Service on a lot of the time but if the DID tune would begin to play, off it goes.

    You’ll probably tell me now they moved it to the Light Programme.

  49. I presume you’ve all seen the photo of John Kerry snogging Mrs Kellner.

    Could Labour exploit her success in the polls do you think?

  50. There is a possibility, of course, that MPs are more likely to stand down where there has been some personal scandal or a government policy has had a particularly bad effect locally.

    So you may have cause and effect mixed up. Perhaps the bigger swings cause the incumbents to stand down, rather than the other way around.

    Also, given the expenses scandal and all that, name checking an MP might not be a positive thing any more. Incumbency may turn negative.

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