Do the Tories do best if more people are voting?

The chart above shows the actual number of votes cast for all parties from 1979 to 2005 and also the total of votes not cast (the paler blue line) from within the overall electorate each year.

For 2010 I have assumed the current state of the polls CON 40%: LAN 28%: LD 19%: OTH 13% (at 75% turnout). Two shapes leap out:

1.The blue Tory and Did Not Vote (DNV) lines are a mirror image of one another, reflecting across a dotted trend line for their average (which is itself on a very slight rising trend); and

2.The Labour and Liberal Democrat lines are also a mirror image of each other, reflecting across a dotted trend line for their average (which is itself on a slight falling trend).

This suggests that the long-term key electoral strategy for the Conservatives must include a big element of getting the vote out, engaging the electorate’s wishes and keeping the political centre right happy. Maybe the UK is an essentially conservative country – but one which struggles from time to time with the Conservative party! The Tories are not fighting Labour or the Liberal Democrats but apathy.

For the political left it suggests that Labour and the Liberal Democrats feed off each other’s votes and that their success strategies should focus heavily on competing to attract each other’s voters. The trends suggest it is as if this fight is independent of the Tory fight against DNV. Maybe this is something of a long running civil war within the political left – and therefore more based on leftwing ideology and less on addressing what the non-voters actually want (as that may not jive with the ideology). If true, it might explain the falling trend.

No wonder Cameron is love bombing the LibDems – every vote they get eats into Labour alone and increases his chances of getting a majority.

Note that the Tory absolute vote result is intimately connected to turnout – equal to turnout in % divided by 3 and then minus 11.5 million (essentially the Con + DNV trend line) to within 2% for every year apart from 1997. 1997 was thus the only election year out of 8 in which the ‘Left’ (Lab + LibDems) takes votes (in absolute numbers terms) away from the ‘Right’ (Tory + DNV) – well done Tony Blair. DNV has a core vote of about 10 million and it seems as if pretty much ALL ‘returning’ votes at higher levels of turnout go to the Tories.

Also noteworthy is that the total vote of the ‘Left’ is a lot less than the total vote of the ‘Right’. DNV has been much the largest political party for over a decade and correctly understanding and influencing their desires and behaviour is the key determinant for the outcome of general elections.

Polls would be much more useful if they also stated an assumption of turnout, as the DNV element is clearly a core driver of results and polls and turnout are not independent events. Models for predicting election results in terms of seats won should use both poll data and turnout assumptions.

I think the 2010 general election is going to have a big turnout – and that will result in a big Conservative victory.

Patrick is a regular poster on PB – this is his first guest slot.