Last week I posted about the predictive accuracy of polls in the 2011 election. Gavin White of UMR wrote to inform me that I’d made a mistake in the formula, so my chart was wrong. Here’s an amended chart. My original point still stands: the Roy Morgan poll isn’t as meaningless as some political commentators and Cabinet Ministers seem to think it is.
I should note that the Fairfax poll is now conducted by Ipsos, not Research International. They still seem to measure National higher than most other pollsters, and New Zealand First quite a bit lower. Also I was intrigued to see the latest Fairfax/Ipsos poll polled 1,011 subjects over three nights. If they’re getting a representative demographic sample in that time then that’s pretty impressive . If they’re not then that’s a bit worrying.