This is a bit of an addendum to the previous post about Angus-Reid. In the future, when profiling a pollster, I will include this information.
I've tried to analyse whether a pollster tends to poll well for one party over another. Now, this is not necessarily a bias. In all likelihood, there is no bias at all. It is merely a reflection of the type of polling system each pollster uses. What I've done is compare a pollster's result to the average result of the other pollsters in a given month. I've limited the analysis to national, Ontario, and Quebec polls because they are large enough that differences can't solely be chalked up to margins of error.
Nationally, Angus-Reid has tended to poll best for the Conservatives. So far this year, Angus-Reid has polled the Conservatives 1.9 points higher than the average. Next on the list would be the Bloc Quebecois, which is polled 0.9 points higher. Then it is the NDP at 0.7 points higher. The Liberals are polled 1.9 points lower than the average, and the Greens 2.2 points lower.
In Ontario, again, Angus-Reid polls best for the Conservatives at 3.2 points higher than average. All other parties are polled lower than the average, the NDP at 0.4 points lower, the Greens at 2.0 points lower, and the Liberals at 2.5 points lower than the average result of the other pollsters.
In Quebec, only the Bloc Quebecois is polled higher than the average, at 2.7 points higher. The Conservatives are polled 0.6 points lower than the average, the NDP 1.1 points lower, the Liberals 1.3 points lower, and the Greens 1.5 points lower.
As more pollsters are analysed, it will be possible to show which pollsters are best for which parties. Looking at these numbers, Angus-Reid tends to be slightly more favourable to the Conservatives, but it is not a huge margin of difference.
NOTE: I am still waiting on the Ontario polling results for the NDP and Greens from the last Strategic Counsel poll. Thankfully, I was promised to be given the information today from a Globe and Mail reporter.
Tuesday, May 19, 2009
Saturday, May 16, 2009
Angus-Reid Polling Trend
Since no new poll is out and I'm still waiting on the full Ontario results in the latest Strategic Counsel poll, I thought we'd look at how individual polling firms have been tracking the trends. Since one would hope polling firms are consistent in the way they poll Canadians, the trends they show from poll to poll are a good demonstration of how parties are doing. When you take all of the polls from all firms together, you get a good indication of actual support. Looking at individual polls shows growth and decline.
So, I've decided to start with Angus Reid, which is my most heavily weighted polling firm. The chart below shows the trend in Canada as a whole, Ontario, and Quebec.
At the national level, there hasn't been very much movement. The Conservatives hit a high of 39% on January 15, and have since dropped to 33% in their latest poll on April 22. From that January poll, there has been a consistent decline of Tory support. However, Angus Reid has been far more conservative in tracking Liberal growth. Michael Ignatieff's party had 31% support on December 12, but that dropped to 29% on January 27. It has since risen to 33%. That is only a variation of four percentage points, as compared with the six-point variation the Conservatives have shown.
The NDP has maintained itself within a three point variation. Their support almost shows a bell curve, with a low 15% on December 12 rising to a high of 18% on January 27, and then dropping back to 15%. The Greens, the hardest party to track, also have a three point variation. They reached a high in Angus Reid polling on December 12 with 8%, dropped to 5% on January 15, and have since settled at between 6% and 7%.
Ontario has shown far greater variation, which is to be expected in smaller regions. The Conservatives, however, were relatively consistent in Angus Reid Ontario polling, maintaining itself at 42% and 41% between December 12 and January 27. The party has since dropped to 38% in the last two polls, which is still higher than most other firms have put them. Thus the Tories have had a variation of four points in Ontario.
The Liberals, on the other hand, have shown a variation of seven points, with a high of 40% on January 15 and a low of 33% on January 27, a great change in a matter of days. They then rose to 39% and first place in the province, but are currently at 35%. The NDP has also shown great variation, with lows of 12% on January 15 and March 11, but hit a high of 19% on January 27 and are currently at 17%. The chart clearly shows that for Angus Reid, the NDP and the Liberals directly split votes, since their trend lines are virtual mirror-images.
The Greens hit a high of 10% on March 11, twice as much as their 5% of January 15, but have since dropped to 7%.
The trend lines in Quebec show much more consistency. The Bloc Quebecois has remained on top, being at 38% and 40% over the last two polls, but dipping to 31% on January 27. The Liberals have shown a steady increase as the Conservative support drops, from 25% on January 15 to a high of 35% on April 22. The Conservatives have fallen away just as the Liberals have risen, maintain a 19% level in January but since dropping to a dismal 10%. The growth of six points for the Liberals between March and April are in line with the drop of six points for the Conservatives. The NDP has also done badly of late, dropping from a high of 17% in January 27 to a low of 6% in April. NDP support was highest when Bloc support was lowest, showing a voting similarity between the two social democratic parties. The Greens have been relatively consistent at 5%.
Compared to the other polling, it would seem that Angus Reid's system is more beneficial for the Conservatives than the Liberals. That isn't to say there is a bias in the system, after all, Angus Reid had the closest prediction in October. And the polling firm has been one of the stronger pollsters for the Liberals in Quebec.
So, I've decided to start with Angus Reid, which is my most heavily weighted polling firm. The chart below shows the trend in Canada as a whole, Ontario, and Quebec.
At the national level, there hasn't been very much movement. The Conservatives hit a high of 39% on January 15, and have since dropped to 33% in their latest poll on April 22. From that January poll, there has been a consistent decline of Tory support. However, Angus Reid has been far more conservative in tracking Liberal growth. Michael Ignatieff's party had 31% support on December 12, but that dropped to 29% on January 27. It has since risen to 33%. That is only a variation of four percentage points, as compared with the six-point variation the Conservatives have shown.
The NDP has maintained itself within a three point variation. Their support almost shows a bell curve, with a low 15% on December 12 rising to a high of 18% on January 27, and then dropping back to 15%. The Greens, the hardest party to track, also have a three point variation. They reached a high in Angus Reid polling on December 12 with 8%, dropped to 5% on January 15, and have since settled at between 6% and 7%.
Ontario has shown far greater variation, which is to be expected in smaller regions. The Conservatives, however, were relatively consistent in Angus Reid Ontario polling, maintaining itself at 42% and 41% between December 12 and January 27. The party has since dropped to 38% in the last two polls, which is still higher than most other firms have put them. Thus the Tories have had a variation of four points in Ontario.
The Liberals, on the other hand, have shown a variation of seven points, with a high of 40% on January 15 and a low of 33% on January 27, a great change in a matter of days. They then rose to 39% and first place in the province, but are currently at 35%. The NDP has also shown great variation, with lows of 12% on January 15 and March 11, but hit a high of 19% on January 27 and are currently at 17%. The chart clearly shows that for Angus Reid, the NDP and the Liberals directly split votes, since their trend lines are virtual mirror-images.
The Greens hit a high of 10% on March 11, twice as much as their 5% of January 15, but have since dropped to 7%.
The trend lines in Quebec show much more consistency. The Bloc Quebecois has remained on top, being at 38% and 40% over the last two polls, but dipping to 31% on January 27. The Liberals have shown a steady increase as the Conservative support drops, from 25% on January 15 to a high of 35% on April 22. The Conservatives have fallen away just as the Liberals have risen, maintain a 19% level in January but since dropping to a dismal 10%. The growth of six points for the Liberals between March and April are in line with the drop of six points for the Conservatives. The NDP has also done badly of late, dropping from a high of 17% in January 27 to a low of 6% in April. NDP support was highest when Bloc support was lowest, showing a voting similarity between the two social democratic parties. The Greens have been relatively consistent at 5%.
Compared to the other polling, it would seem that Angus Reid's system is more beneficial for the Conservatives than the Liberals. That isn't to say there is a bias in the system, after all, Angus Reid had the closest prediction in October. And the polling firm has been one of the stronger pollsters for the Liberals in Quebec.
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