Tuesday, March 24, 2009

So the Ipsos Reid Polling Numbers are in

The numbers indicate that there is a large gap between the NDP and the Liberals, large enough to signal a landslide for the Liberals if they hold through to the election. The Ipsos Reid numbers have been consistent for three years now.

  • Liberals - 46%
  • NDP - 35%
  • Greens - 15%
  • Others - 4%
I do not have access to the full report and therefore I can not see some of the more relevant data, specifically how many people will not vote. Typically in most polls there is a higher percentage of the population that indicates a party preference than the people going to the polls. In an 800 person poll, about 250 to 300 of the respondents will not be voting, unless they do not use these responses. Normally what I see in polls is people listed as do not know and not will not vote. The do not know numbers tend to be a much smaller percentage of the actual non-voters. The only clue we get in the polls of voter intention is the numbers that relate to how firm people are in their choice - Liberals 70% firm, the NDP 60% firm and the Greens 50%. If we use these numbers we end up with:

  • Liberals - 32.2%
  • NDP - 21.0%
  • Greens - 7.5%
  • Others - 1.0% (my own estimate based on past performance)
  • Floating voters - 38.7%

I think this gives us a better indication of what the data is saying. The NDP has only secured their core supporters at this time. The Liberals have a commanding lead. Most of the floating voters are not likely to vote.

Looking back on late 2004 and early 2005, the NDP had a higher committed vote than this time and the Liberals lower - the Greens were in the same shallow support as now.

On the basis of the Ipsos Reid numbers, I am broadly sticking with my existing projections for the election, but I will move Vancouver Kensington into a likely Liberal win rather than a toss up as I had been thinking it would be.

I know people are looking for regional break downs, I am not very interested because the data will be too erratic to indicate much at all. At 800 people the margin of error is +- 3.46% at a 95% confidence level. I am actually generally disappointed how few people that look at polls understand the math behind them. The fewer respondents you get, the broader a bell curve you get on the range of values and the less likely the 'reported' value is actually the true one. It would be helpful if the pollsters released the data with several confidence levels, it would give people a better understanding of what the numbers mean. You can do the math yourself.

The margin of error is only relevant to the statistical math going on, it does not account for other errors in the polling through people not being honest in their answer or systemic errors by the pollster. For this poll it is +-4.56% at 99% confidence and +- 2.90% at 90% confidence.

The regional breakouts of an 800 person poll would lead to +- 4.9% at 95% confidence for the whole lower mainland. For Vancouver Island we would have an error of +-8.3% at 95% confidence. What these sort of numbers mean is that any results would have very flat curves and really are no better than hamburger polls in restaurants.

I would like to see some 2000 to 3000 person polls conducted to give us some data with better data and with some real regional numbers to work with.

I am looking forward to the next Mustel poll and see what it can tell us.
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