Illuminating observations from the inventor – UKPR’s Anthony Wells

There’s a big debate going on over the Lord Ashcroft style two stage questioning in his single constituency polls of which there have been more than 150. It will be recalled that after asking the standard voting question he puts a second one suggesting that those sampled focus on their own seat and the candidates who might stand.

The numbers that are highlighted are the responses to the latter not the former. In his CON-LD seat polling the two stage approach is producing very striking results suggesting that there will be fewer easy pickings for the blue team than might appear from national polling.

The issue, which could be crucial given the importance of the blue-yellow battleground to the outcome on May 7th, is how much the Ashcroft approach can be trusted. The good news is that it was tested in a limited fashion by UKPR’s Anthony Wells prior to GE10. He wrote recently:-

“Personally I have confidence in the two-stage constituency question. It’s something I originally used in marginal polling for PoliticsHome back in 2008 and 2009, to address the problem that any polling of Lib Dem seats always seems to show a big jump for Labour and a collapse for the Lib Dems. This would look completely normal these days of course, but you used to find the same thing in polls when Labour were doing badly nationally and the Lib Dems well. My theory was that when people were asked about their voting intention they did not factor in any tactical decisions they might actually make – that is, if you were a Labour supporter in a LD-v-Con seat you might tell a pollster you’d vote Labour because they were the party you really supported, but actually vote Lib Dem as a tactical anti-Tory vote. The way that it only has a significant effect in Lib Dem seats has always given me some confidence it is working, and people aren’t just feeling obliged to give as different answer – the overwhelming majority of people answer the same to both questions.

However the fact is the two-stage-constituency question is only theoretical – it hasn’t been well tested. Going back to it’s original use for the PoliticsHome marginal poll back in 2009, polling in Lib Dem seats using the normal question found vote shares of CON 41, LAB 17, LDEM 28. Using the locally prompted second question the figures became CON 37, LAB 12, LDEM 38. In really those seats ended up voting CON 39, LAB 9, LDEM 45. Clearly in that sense the prompted question gave a better steer to how well the Lib Dems were doing in their marginals… but the caveats are very heavy (it was 9 months before the election, so people could just have change their minds, and it’s only one data point anyway.) I trust the constituency prompted figures more, but that’s a personal opinion, the evidence isn’t there for us to be sure..”

To my mind Anthony is right that the consistent pattern of this only showing big differences in LD seats suggests that something different is happening in those battles that should be taken into account.

Certainly, looking at the betting prices in CON-facing LD seats, punters appear to putting their money behind the two stage approach.

The LD are literally betting the party at the election on their individual candidates being the main selling point. They are effectively running “Mayoral election” type battles.

Not long to wait till the early hours of Friday May 8th when we’ll know for sure what’s happened.

Mike Smithson

For 11 years viewing politics from OUTSIDE the Westminster bubble

For latest polling and political betting news follow @MSmithsonPB