More on poll accuracy

KB reader Nik has sent in an updated version of his graph measuring the difference between the average of polls released in the two days before an election, and the actual results. His changes are based on reader comments.

You can see that the difference have been fairly minor – generally within 1.5% each way. National and Greens tend to do worse than the polls show by around 1% to 1.5%.

Despite what Winston claims, the polls for the last two elections have had him within 0.5%. In fact in 2005 his result was slightly less than the polls.