The Trouble With Polls

Pollara says the Conservatives are surging ahead at 36%.

Decima says the Tories are falling back to 29% behind the Liberals.

Decima polled slightly over 1,000, and Pollara polled 1,250 Canadians. Pollara polled between April 27 to May 1. Decima polled between April 28 to May 2.

That difference is way over the margin of error for both polls. Something else is going here.

There is only one day's difference in terms of polling between the two polls. Really that means either something happened on April 27 to boost Tory support or something happened on May 2 to downgrade Tory support.

Let's look at a sample of the headlines for April 27:

Farmers get 'hope' from Harper
London Free Press, Canada - 27 Apr 2005

Harper blasts NDP-Liberal deal
Globe and Mail, Canada - 27 Apr 2005

Harper: Tories won't back 'NDP budget'
National Post, Canada - 27 Apr 2005

Harper vows to take down Liberals
National Post, Canada - 27 Apr 2005

Harper welcomed in rural Ontario
Times & Transcript (subscription), Canada - 27 Apr 2005

Canada Opposition to Push for Gov't Defeat Soon
Metro Toronto, Canada - 27 Apr 2005

PM grabs NDP lifeline
London Free Press, Canada - 27 Apr 2005

Martin buys NDP support
Globe and Mail, Canada - 27 Apr 2005

PM pins hopes on NDP lifeline
Toronto Star, Canada - 27 Apr 2005

VE Day absences drawing more fire
Globe and Mail, Canada - 27 Apr 2005

Tax cuts would survive under Tories
Canada.com, Canada - 27 Apr 2005


Here is a sample of the headlines for May 2:
Harper's left turn needs explanation
Toronto Star, Canada - 2 May 2005

Peter Kent to run for federal Tories
National Post, Canada - 2 May 2005

Tories gag returning MPs
Winnipeg Sun, Canada - 2 May 2005

Pathetic Paul and Lame Layton
Edmonton Sun, Canada - 2 May 2005

Ottawa starts medicare crackdown in NB over unpaid abortions
National Post, Canada - 2 May 2005

Goodale sticks by budget changes
Edmonton Sun, Canada - 2 May 2005

Paul Martin Orders Veterans Affairs Minister and MP Back To Canada
Halifax Live, Canada - 2 May 2005


There were a couple negative headlines on the 2nd, but not much. The real explosion of activity was on the 27th with a flurry of headlines on the NDP/Liberal deal. What I really think happened is that the difference between the two polls can be summed up by the publics initial reaction to the Liberal/Socialist deal. Decima did not poll during that period and waited until after the public anger had subsided. Then over the weekend and on the monday we heard all about the Tories gagging MP's and Harper making a left turn...

What this means is that a difference of one day can shift the numbers by 7%. This is anybody's election folks.

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