Within hours of each other last week, two opinion polls gave spectacularly different results as to voter preference in the 2014 race for mayor of Toronto.

Mainstreet Technologies, a relative unknown outfit that started polling this race in September, reported that 42 per cent favoured John Tory — a 14-point lead on Doug Ford (open Doug Ford's policard) (28 per cent) and more than twice the 19 per cent support for Olivia Chow.

Forum Research, a constant bellwether in this race since last spring, shocked everyone — including its own president, Lorne Bozinoff — with a result showing John Tory (at 39 per cent and Doug Ford (37 per cent) just two points apart.

Organizers behind Tory’s campaign laughed it off as a “rogue poll.” Days later, their numbers still had Tory up by double digits on Ford, with Chow dropping below 20 per cent.

Two weeks earlier, Forum’s own numbers put the frontrunners at Tory 38, Ford 31, Chow 22. It’s not a huge stretch, then, using Forum’s numbers, to see Tory drop 1 point, Ford rise 6 and Chow drop 4.

But that Forum result, when compared with a less publicized Forum poll done Sept. 29, a week earlier, sparked disbelief among several election watchers. That Sept. 29 poll gave Tory a 10-point lead (43 to 33) over Ford. Nobody could point to anything that would have chopped a 10-point lead down to two in one week.

More: The Star’s Toronto Mayoral Election Poll Tracker

What created the dissonance for anyone trying to read voter preference is that all the other polls over the past month showed a big gap between Tory and the nearest challenger, Ford, ranging from 17 points (Mainstreet) to 22 points (Ipsos).

There is no quick and easy way to decipher the polls. My tried-and-true approach is to “wait for the next one.” If the next poll follows a trend line and rings true with the feedback I get on email responses, on the bus, at church, at the barbershop and at the numerous debates, then it is likely correct.

As such, the last Forum poll result strains credibility. Unless, of course, Forum happened to ask the questions just at the time when the tide was turning towards Ford.

That’s why you always wait for the next poll.

Nik Nanos, of the Ottawa-based polling firm that has consistently shown Tory to be in front, (up 6 points in July, 12 points in August and 21 points in mid-September) says another good strategy is to compare the polling results from one pollster to the other.

The Toronto mayoralty has attracted Forum, Nanos, Ipsos, Mainstreet Technologies and Maple Leaf Strategies, a Conservative party polling firm that correctly called the outcome of the 2013 B.C. election.

If three pollsters say one thing and the fourth pollster is at odds, then odds are the outlier is wrong, Nanos says. That is, until others confirm the most recent finding.

Journalists might provide some more guidance in reporting on polls — stressing the different methodologies used, trend among polling results from comparable pollsters, and offering reminders that the results represent a snapshot in time.

We could argue for a long time about automated telephone surveys versus live person interviews. Or sample size. Or time of day the survey is done. Or whether accuracy is more likely over three days as opposed to a quick poll over four hours one evening. Methodology matters.

But one key factor to help you understand a poll is whether or not the result is for all persons interviewed, or only for those likely to vote, or of those who have made up their minds.

For example, Forum polls all eligible voters — including those who may or may not vote. In this race for Toronto mayor, Forum’s methodology automatically produces results that make the race appear closer than it is.

Why?

Results from most all of the pollsters show that Ford’s support is strongest among those who are least likely to vote, citizens younger than 35. For Tory, the opposite is true. His support spikes among the over-65 crowd and is equally large among the middle-aged voters who normally vote. So, if all voters are included in the polling sample, the result will show Ford with more support than he is likely to get at the polls. But if the poll counts only those likely to vote, Tory’s numbers rise.

Nanos says his firm reports results only for the “hardcore municipal voters,” the people who historically show up at the polls. If you tell the Nanos questioner that you are “somewhat likely to vote,” your answer is screened out. Forum, meanwhile, in its Oct. 6 poll, is reporting on voters who have “decided and leaning towards” a candidate.

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“So, if there is a high voter turnout on election date, (Forum’s results) are likely to be more accurate. If the turnout is average, expect Nanos to be closer to the mark,” Nanos said.

Bottom line on the Oct. 6 Forum poll? Wait for the next one. If another pollster replicates the narrowing of the field, then Bozinoff caught the wave of support trending Ford’s way.

If not, Forum went “rogue” last week. It happens. And we won’t have to wait till voting day to find out. There will be as many as three or more polls before Oct. 27. Read them all and wait for the next one.

Royson James usually appears Tuesday, Thursday and Saturday. Email: rjames@thestar.ca

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