My last but one post about Hung Parliaments – which is really just the IoD on hung parliaments – has done so well over a sleepy weekend that I feel a little embarassed: I really added nothing! So I feel I should try to add something. My own scatter chart for once.
I am going to beef up my Swingometer to a ludicrously overblown level, so that I can enter results as they come in, work out what they seem to be implying about the final result, speculate a little, that sort of thing. But there are serious assumptions to tease out first. For example: how swingy is the swing? Last election the anti-Labour swing averaged about 6 points. But its standard deviation was 4.5 points – so only about 66% of results would fall between -1.5 and -10.5. Worth bearing in mind if a freak result comes in.
But the second point that had me thinking was this: if you get a result in a seat that ‘counts’ i.e. that is in play – should one expect it to be typical? A seat with a Labour majority of 10% – did it swing more than one with 30% or 5%? If so, you might get results far more extreme than under the uniform swing. Note: this is not (yet) about tactical voting (the lost votes going to the appropriate other party).
The scatter chart below suggests that this did not happen in 2005:
Sorry, a mess of dots. The basic results are: the swing from Labour was about 2% less in Tory held seats than in Labour held seats – which is what a Tory strategist would want. But the red dots are downward sloping but not downward sloping enough; there are a lot of ‘swung’ votes that took place in very strongly held Labour seats.
To put it more exactly: the average swing in Labour held seats was 6.8% against Labour; but it averaged 5% in those with a majority in 2001 of less than 10%, and 7.15% in those with higher majorities.
Perhaps back then people voted against Labour more as a protest – when they felt it was unlikely to overturn their MP? Who knows. I’ve done 20 minutes on this and have a sore back. But I doubt conditions are anything like the same now.