10:59 am - October 8th 2012
A lot has been written about how the constituency boundaries mean that Tories face a tough challenge to win the next election. For example, top pollster Peter Kellner argues, “For the Conservatives to win an overall majority, they need around a seven point lead in the popular vote.”
In contrast, the Mail on Sunday reports that Tory strategists ‘are confident that incumbency gives them an advantage’ as they plot how to win the next election.
Let’s have a look and find out who might be right.
The case that ‘incumbency advantage’ could make a large difference is that at the next election in a constituency which the Tories gained in 2010, the Tories will have benefited from having an MP building up their profile, recruiting volunteers, raising funds and campaigning for five years.
In addition, the Tories will have received over £150,000 per year in state funding for the MP’s salary, office costs, free postage of letters and a team of staff. Between 2010 and 2015, in the top fifty marginal constituencies which Labour is seeking to win from the Tories, the taxpayer will have provided in excess of £35 million to help the Tories defend their majorities. On top of this, these are all seats where Labour used to have an incumbency advantage (which will have helped them at the 2010 election), but where they are now forced to cope without these resources.
There are some numbers to test the ‘incumbency advantage’ hypothesis. Professor Philip Cowley reports that, ‘In 2010, Labour’s vote fell by an average of 7.4 percentage points in its seats that were not defended by the incumbent MP, more than two points higher than the equivalent statistic in seats where the incumbent stood again (–5.2).
The Conservative vote rose on average by 2.9 percentage points in Conservative held seats that were not being defended by an incumbent, but 4.1 points where the incumbent MP was still in place. And incumbent Conservative MPs who first won their seats in 2005 – and who thus had the opportunity to acquire a personal vote for the first time – saw their vote increase on average by 5.6 points.’
To estimate what effect this incumbency effect might have, let’s compare two scenarios. In one, we assume a close election, with some recovery for the government compared to the situation now, where Labour and the Tories each get 38% and the Lib Dems 15%. In the other scenario, we assume the same level of support nationally, but in addition apply a 2% swing to the incumbent in all seats where there is an MP restanding for the first time. This is a cautious estimate, when compared to the 5% swing to first time Tory incumbents which Joan Ryan found in her research on the 2010 election, but should give us an idea about whether this matters.
Using Electoral Calculus’ election predictor, the first scenario gives Labour 321 seats, 281 for the Tories and 23 for the Lib Dems.
But if we add in the effect of incumbency as above, then by my quick tally, we get 302 seats for the Tories, 298 for Labour and 25 for the Lib Dems. The whole of the supposed ‘bias’ in the electoral system towards Labour from the current boundaries disappears.
Let’s consider one further effect of incumbency. To get a majority, the Tories will be attempting to win seats from their coalition partners, the Lib Dems. Again, there is some evidence that Lib Dems benefit from having an incumbent MP. So let’s assume that the incumbency bonus above also applies to all Lib Dem MPs. Then we would end up with the following result:
Labour 298 Tory 294 Lib Dem 33
So, in summary:
Past evidence and local results since 2010 suggests that there is an ‘incumbency effect’, particularly for MPs elected for the first time in 2010.
The benefits of incumbency mean that it is harder for either Labour or the Tories to win an overall majority, as they have to battle against incumbent MPs who have large amounts of state funding to bolster their campaigns.
The Lib Dems are likely to do better than suggested by election predictors which don’t consider the benefits of incumbency.
Don Paskini is deputy-editor of LC. He also blogs at donpaskini. He is on twitter as @donpaskini
· Other posts by Don Paskini
Story Filed Under: Blog ,Conservative Party ,Labour party ,Libdems
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Reactions: Twitter, blogs
- Jason Brickley
Why ‘incumbency advantage’ may decide the next election http://t.co/A8yaexLo
- Phil BC
Great post by @donpaskini on the electoral effects of incumbency: http://t.co/CMC7UwVP
Liberal Conspiracy – Why ‘incumbency advantage’ may decide the next election http://t.co/a0poEA1Y
- Don Paskini
@MikeSmithsonPB @anthonyjwells would be interested in your thoughts on attempting to measure the 'incumbency effect' http://t.co/BWeFue8q
RT @libcon: Why 'incumbency advantage' may decide the next election http://t.co/TN29ScJN
- UK Polling Report
[...] Paskini has linked to some of the attempts to measure incumbency bonus in a piece for Liberal Conspiracy her…, but the effect of incumbency is probably about 1.2% – 2% of the vote (or double that for [...]
- Mark Thompson
Why ‘incumbency advantage’ may decide the next election http://t.co/ay0rB6qN (via Instapaper)
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