Incumbency and the sophomore surge: why these two effects will matter for the Lib Dems in 2015

Lib Dems winning hereWith the Lib Dem vote at least halved in the polls since the last general election, there’s been much focus within the party on what’s known as the ‘incumbency effect’ – the personal vote that benefits Lib Dem MPs. This typically boosts Lib Dems by 8%, compared to 1-2% for Tories and 1.5-2.5% for Labour MPs.

It’s this effect which, Lib Dems hope, will enable the party to buck the national trend at the next election. It is, however, limited to those seats where the current MP will re-stand: currently nine Lib Dem MPs, 16% of our 57 MPs, have announced their retirement. In those nine seats the party will lose that incumbency effect – in effect, starting c.8% behind its position in 2010.

There is another electoral effect – the ‘sophomore surge’ – which may well also have an impact: this is the additional polling bounce a first-time MP gets when up for re-election. The Lib Dems have 11 first-term MPs (if you include Eastleigh by-election winner Mike Thornton), 19% of our 57 MPs, who would expect to see at least some degree of sophomore boost to their positions.

The effects of both incumbency and the sophomore surge have been calculated by Tim Smith, a PhD student at the University of Nottingham, on the Ballots and Bullets blog.

Let’s start with the bad news: “even before there is any swing against the [Lib Dems], they are four seats down, purely due to retirements.” Those four seats are Berwick-upon-Tweed, Mid Dorset & Poole North and Somerton & Frome (all with Tories in second place) and Brent Central (Labour). Sir Malcolm Bruce’s Gordon constituency is also seen as risky.

But there is better news:

The effect of having ten first term incumbents is that some of the party’s seats will become easier to defend. The distribution is also important since seven of the ten seats are in constituencies with majorities under 5% of the vote over the nearest opposition party. This will mean that if there is a swing against the party, the number of seats beyond those already expected to go due to retirement effects might well be lower than would otherwise have been expected. The adjusted majority of the 20th safest seat the Lib Dems have on paper is 7.34%. Taking incumbency into account the 20th safest (including the 4 that would be lost) would be larger at 8.28%. Therefore with a theoretical swing of approximately 4% against them, the Liberal Democrats end up having more seats once incumbency is taken into account than they would on paper.

Liberal Democrat MPs have much larger incumbency advantages than those of other parties and this is likely to have important effects at the next election. The balance of the effects improves the worse the party does: a tiny swing towards the Liberal Democrats might see them losing seats, all other things being equal, whilst a large swing against them might be partially mitigated by having so many first term incumbents.

* Stephen was Editor (and Co-Editor) of Liberal Democrat Voice from 2007 to 2015, and writes at The Collected Stephen Tall.

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This entry was posted in Op-eds.


  • Joshua Dixon 4th Aug '14 - 9:20am

    The difficulty in measuring this is we do not know if our incumbency strength has been hit by being in coalition. I think the 8% figure, although accurate in the past, may not be as reliable this time around.

  • Charles Rothwell 4th Aug '14 - 9:27am

    Oh dear. I am afraid all this stuff is way beyond a simple Party member/voter like me who (naively?) sees matters like attractive policies which the electorate and Party activists can believe in and work hard to achieve while presenting a clear vision plus charismatic/appealing leadership as the crucial factors.

  • Joshua Dixon 4th Aug '14 - 9:29am

    @Stephen – Yes, I should have been a bit clearer! The Ashcroft polling is very interesting, however, unless he uses questioning that directly uses the names of candidates (as I know the likes of Mike Smithson will be advocating) I’m not sure how accurate it would be.

  • Though this is encouraging, I wonder what we can do to offset the damage caused by people not understanding coalitions, so we get blamed for “abandoning our principles” rather than congratulated for curbing Tory excesses, (so the country is in a better place than it would have been with a Tory majority government), and enabling government to work well despite major differences of opinion (and certainly to work better than the Tory-only government did in the John Major years).

  • Calderdale_Local 4th Aug '14 - 9:46am

    4% swing against??????

    The aspect that worries me is the number of seats where our local election vote ran ahead of our Parliamentary vote in 2010 and where we are now running significantly behind our main opponent. This analysis requires quite a big reversal of that trend and is relying on something fairly slender in regard to an incumbency factor.

    Remember that in 2010 the party was on a wave of popularity which would have been higher (and easier to maintain) in held seats. Are those figures quoted for incumbency benefits from a number of elections – and which ones?

    And to run an incumbent strategy in a held seat requires you to put yourself as a bit of an independent with some distance from the government/national party. This isn’t what seats are being advised and equipped to do.

  • The trouble about projections of results at the next election made by academics is that they do not take account of the electoral situation at individual constituency level. Regretfully, I think that we must be resigned to losing Somerton and Frome, and maybe also Gordon, but the notion that Berwick-on-Tweed, held by Sir Alan Beith ever since 1973, will be an automatic loss on his retirement, is a strange one, especially as the only viable contender to gain the seat is the Conservative candidate and the national swing from us to the Tories since 2010 is not all that severe. Similar considerations apply to Mid Dorset and Poole, and it is important to bear in mind that Alan Beith and Annette Brooke will remain in harness right up till the end of the parliament and will no doubt be campaigning vigorously on their successors’ behalf.

  • Incumbency works when you do, what you say you intend to do. (Or at least try). So incumbency has more traction at the council level, where LibDem councillors have worked their socks off to make sure the bins are emptied on time, and potholes are filled as promised etc.
    However, an MP who made principled statements prior to their election in 2010, only to cynically walk shoulder to shoulder with other unprincipled colleagues, through Westminster voting doors that they said they wouldn’t, have frankly made a bonfire of their incumbency.

  • Matthew Huntbach 4th Aug '14 - 11:23am

    Mark Argent

    Though this is encouraging, I wonder what we can do to offset the damage caused by people not understanding coalitions, so we get blamed for “abandoning our principles” rather than congratulated for curbing Tory excesses

    We are still being hit by the grave mistake made at the start of the coalition with the Rose Garden presentation of the two parties being almost equal partners, and Nick Clegg looking so pleased with himself about being “in government”. Although I mention this again and again on LDV, I’m always being hit by the same thing again when I talk to people who aren’t LDV readers, aren’t that involved or particularly interested in politics, but have in the past been sympathetic to the Liberal Democrats. That image and the unrealistic expectations it built up have stuck with them. Somehow the initial sales pitch we put forward for the coalition has stuck with them – they really did think it would be a completely different form of government that would be much more people-friendly and oriented towards their concerns because it would be “politicians from different parties working together instead of fighting each other”, and they are bitterly disappointed to find it seems to me very much a Tory government, doing all the things they voted LibDem not to have, with the same old political tit-for-tat going on, only now the LibDems have been subsumed into the Tories.

    It seemed to me clear from the start that the balance of the two parties and the lack of the possibility of a stable Labour-LibDem government meant the coalition government would inevitably be following the policy direction of the Tories, with the LibDems able only to influence at the fringes. We should have made this clear at the start, and pointed out that it is an inevitable consequence of the way people voted in May 2010 and the distortions of the electoral system. Because we would undoubtedly be hit by “You put the Tories in just to get comfy government jobs for yourselves”, we should have gone all out to avoid any “looking pleased with ourselves” imagery, and more so because whatever government there was from 2010 onwards would have to do things that would make it unpopular due to the economic situation. We did the exact opposite. Those responsible at the top of the party for doing the exact opposite should be sacked. They have proved gravely incompetent. They have made a difficult situation much worse by taking us down a public image route that anyone with a bit of party sense and experience could see then would be a damaging one. Look at coalitions in other countries, and balance of power situations in local government here, to see how the inevitable attack lines would work, and how we wouldn’t come across as national saviours for agreeing to the only government that would work given the Parliamentary balance.

    Would it help to put out the line “OK, suppose all three parties stood by their principles and so voted down anything proposed by either the of the other parties, then what? Do you really think a situation of impasse in which the country is ungovernable because each party refuses to concede to the others would have been good?”.

  • Matthew Huntbach 4th Aug '14 - 11:34am

    Charles Rothwell

    Oh dear. I am afraid all this stuff is way beyond a simple Party member/voter like me who (naively?) sees matters like attractive policies which the electorate and Party activists can believe in and work hard to achieve while presenting a clear vision plus charismatic/appealing leadership as the crucial factors.

    Why is it way beyond you? When people vote in general elections, yes they think they are voting for “a government”, but there is also a very strong sense of voting for a local representative, so MPs that have come across well in doing that role do stand an advantage.

    I think also we need to accept that as we are unlikely to be forming a majority Liberal Democrat government after the next general election, running an election campaign on that basis, putting it across as all about the policies such a government would have and the person who would be leading it is a bit silly. We need to move politics away form that model and towards one which accepts politics is about electing representatives we can trust who come together to work out policies that can get majority support. Putting it in that way might also help get out the message about how the coalition actually worked – of course we could not get through every policy we would want, we have taken part in policy negotiations to get what has come out of this government, but what you see is what you might expect from there being five times as many Tory MPs as LibDem MPs.

    Given that the party’s national image is in a mess, the next general election will have to be fought defensively, and putting the emphasis on the good record of our MPs and asking for a local vote for them is a good way of doing it. It is NOT a good long-term plan for the party, but in the short-term to ensure we have a reasonably sized Parliamentary party after the next election, we’ll have to go for it.

  • For goodness sake, Stephen, why do we have to import US terms such as “sophomore”? It’s bad enough to have “buddy”, and “intern” imposed on us in employment jargon.

  • Stephen Hesketh 4th Aug '14 - 9:55pm

    Tim13 4th Aug ’14 – 8:32pm
    “For goodness sake, Stephen, why do we have to import US terms such as “sophomore”? It’s bad enough to have “buddy”, and “intern” imposed on us in employment jargon.”

    Totally agree Tim … and, as if under pain of death, ‘forthcoming’ has been swept away and replaced by ‘upcoming’, leverage (leeverage) being replaced by lev-er-age), ’24/7′, ‘reach out to’ … it goes on and on … and on. Top of the programme. No its a bloody programme not a script etc on a piece of paper!

    The, ‘oh so very smart, I’ve lived in the US’ television reporters are the worst for introducing them here only to be absorbed and spread by lovers of corporate-speak etc.

    Oh, I do feel better getting that off my chest 🙂

  • Stephen Hesketh 5th Aug '14 - 1:08pm

    @Charles Rothwell4th Aug ’14 – 9:27am. Being a follower of your posts, I’m quite sure your comment was not meant to be taken literally 🙂

    I certainly agree with the Stephen’s incumbancy factor though. Voter satisfaction with a sitting Lib Dem MP has been shown to be consistently higher than for the other parties. Let’s hope that it transfers when we have new candidates!

    Several good comments/observations also made by both Caractatus and Matthew Huntbach.

  • Matthew Huntbach 8th Aug '14 - 10:44am


    For goodness sake, Stephen, why do we have to import US terms such as “sophomore”? It’s bad enough to have “buddy”, and “intern” imposed on us in employment jargon.

    Yes, and what about that other phrase we seem to hear a lot of now “step up to the plate”? It’s to do with the version of rounders that they take seriously in the US, but the British term should be “come to the crease” i.e. a cricket analogy. Or what about “gotten”, which when I was young was considered a really weird Americanism, but now one finds is very often used by younger British people.

    Now, one might say isn’t resisting these things just a form of xenophobia, what’s wrong with the restoration of the old past participle of the verb “to get” which had been lost in British English but retained in US English?

    To me, it’s not the surface thing here that’s the issue, it’s what it may be a symptom of going on underneath. When I’ve queried the use of “gotten” form British people, I’ve found it’s generally done subconsciously, they are not trying to sound American. So, if Americanisms can slip into basic grammar in an unconscious way, what else from the US is slipping unconsciously into our ways of thinking and acting?

    The US is a very different country from Britain. The huge amount of land it has per person compared to us, and its relative geographical isolation are two aspects which mean a way of thinking that works in the US won’t work in Britain. So, my fear is that harmless things like the restoration of “gotten” may be indicative of a more harmful influence coming from the US dominance of the English-speaking world.

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