Why the bias to LAB in the electoral system could be even more pronounced at GE2015

Why the bias to LAB in the electoral system could be even more pronounced at GE2015

Anti-CON tactical voting could be much greater

The big polling news yesterday was that in the Ipsos-MORI monthly phone survey the LAB lead amongst those certain to vote was down to just 4%. Suddenly a glimmer of hope appeared to be opening up for the Tories. Yet when these numbers were put into the Electoral Calculus HoC seat predictor LAB had a majority of 30 with a vote share of just 34%. That is 3% below what the Tories achieved in 2010 when they were 19 MPs short of a majority.

    Seat projections like these put the focus on one of the basic characteristics of how Britain’s first past the post electoral system operates: it sets the bar for a LAB majority at a much lower level than for CON leading to inevitable shouts of “foul”.

Part, but only a small part, is down to constituency sizes. On average in 2010 LAB seats had smaller electorates, 68,612 than CON ones (72,435) but that gap is much smaller than is widely perceived.

A second measure is more striking as can be seen in the second comparison on the above chart – the average number of votes cast in LAB seats, 41,842 is considerably lower than the 49,436 that we saw in 2010. This is largely because turnout levels are significantly lower in LAB seats – see bottom chart.

There’s also another factor – what happens in seats where the parties are third. The Tories pile up higher vote levels than LAB boosting overall national vote shares but making no contribution in terms of seats won.

Compared with GE1997, GE2001 and GE2005 there was much less anti-CON tactical voting at GE2010. That could return next time particularly in the 100 or so key marginals where the election will be decided. This was shown in some of the Ashcroft marginals polling when people were asked what they would do in their own constituncies.

I live in the 20th most vulnerable Tory seat to Labour and the level of activity by the red team even at this stage is impressive. LAB canvassing teams are going out every week and they are putting a special on reaching known LD supporters. The Tories, it should be noted have been largely invisible.

Mike Smithson

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