The great Anthony Wells found my last post on polling shifts interesting, but gently chides me for comparing what’s happened to 2010 voters without considering how many have shifted to saying they don’t know or won’t vote.
It’s a fair cop. My only defence is that YouGov don’t make it easy to include the data. (They total 2010 voters by current voting intention, express that as a percentage, then separately tell us the share saying they don’t know/won’t vote, which makes it a pain in the bum to restate the data on your coffee break.)
That said, Anthony is quite right to say the proportion of each party’s 2010 voters who are now unsure or planning to abstain is important, so I went backhad a look, comparing the past week’s polls and those of a week in December.
The results are not that earth-shaking. Labour’s 2010 voters are slightly less certain to vote than they were six months ago, but are still much more likely to vote than either those who voted Tory or Lib Dem in 2010.
You might argue that a proportion of these Tory and Lib Dem 2010 voters will return to their party, or you can argue that this adjustment is already taken into account by polling methodologies (if not by Yougov, then by other pollsters).