The only poll that matters is election day. Really?

Vassy Kapelos, host of Power & Politics

My question to the Power Panelists was dismissed within seconds.

"Guys, what do you read into these numbers right now?" I asked.

Two of the panelists rejected the premise of my question almost immediately, reminding me that "the only poll that matters" is the one that happens when Canadians cast their ballots on election day.

I take their point. I think I've heard their point (in scrums, interviews and Power Panel discussions) about 300 times by now. Of course the only vote that "matters" is the one on election day (which, by the way, is exactly three months away).

But these pre-election polls matter, too. And at least one (OK, only one) panelist agreed with me. "We do look at those numbers," said former New Democrat MP Françoise Boivin. "Anybody who says otherwise is kidding you."

A woman enters Maple High School in Vaughan, Ont., to cast her vote in the federal election on Oct. 19, 2015. Voters go to the polls this year on Monday, Oct. 21. (Peter Power/Canadian Press)

But how do they matter? There's no easy answer to that one. Polls, and how journalists report on polls, get a lot of scrutiny in the run-up to an election. I'm OK with that scrutiny; we in the media have gotten polls wrong before. And a lot of people are sick of the horse-race reporting. I get that.

Still, there's value in examining a poll's description of voters' feelings at certain points in time. We know, for example, that the SNC Lavalin story had an impact on Canadians' perceptions of Prime Minister Justin Trudeau and the Liberals — because polls told us it did. We also know (from polls) that the impact of that controversy has faded since. Regional polling breakdowns are helpful too: we know the NDP is struggling in Quebec and we know the 905 area surrounding Toronto will be a key battleground.

All of which helps us to understand why politicians choose to campaign in certain ridings, why they embrace certain policies and which demographics they're trying to target. Polls also help us understand their vulnerabilities and evaluate whether they can overcome them.

But not all polls say the same thing — recent polls have shown a wide inconsistency in federal results — and interpreting them can be hard. My colleague Éric Grenier is better equipped to tackle that question, as he does a bit later in this newsletter. Parties do their own internal polling, of course, and it helps to drive a lot of decision-making during a campaign. Notice how Justin Trudeau talks about Doug Ford far more often than he mentions Andrew Scheer? There's a reason for that: internal polling shows the Liberals that it's an effective approach.

So three months out from E-Day, polls tell us how Canadians are feeling about their representatives and which issues are important to them. They don't tell us for certain what's going to happen in October. As long as everyone gets that, we're good.

After all, the only poll that really matters is the one on election day. (Or so I've been told.)

Vassy Kapelos is host of Power & Politics, weekdays at 5 p.m. ET on CBC News Network.

Power Lines

The Power & Politics Power Panelists on where the big parties will be focused this week.

Amanda Alvaro president and co-founder of Pomp & Circumstance

Liberals will be highlighting how the Canada Child Benefit is increasing again this week to keep up with the cost of living and help families get ahead. They'll be reminding Canadians that the Conservatives voted against the CCB — a program that has provided more money to families tax-free, and has lifted 300,000 kids out of poverty — in favour of their practice of sending cheques to millionaires.

Rachel Curran senior associate at Harper & Associates Consulting

Conservative Party Leader Andrew Scheer will be spending next week in Quebec, meeting as many Canadians as possible. He will be continuing to highlight the cost-of-living crunch that many Canadian families are facing and pointing out that Justin Trudeau is "Not as Advertised."

Kathleen Monk principal at Earnscliffe Strategy Group

New Democrats are in "The Six" (Toronto) this week, talking about the affordability crisis. Jagmeet Singh kicks things off with the nomination of three Brampton candidates. He'll then spend the week doing GTA media. New Democrats plan to engage as many voters as possible, arguing that if we want better results for people, we must make different choices than the ones Liberals and Conservatives have made.

Poll Tracker Takeaway

Éric Grenier's weekly look at key numbers in the political public opinion polls.

If you were confused by the polls this week, nobody blames you.

Nanos Research says the Liberals are ahead by six percentage points. Campaign Research gives them an edge of just one. Then there's Ipsos , which puts the Conservatives ahead by six points, and the Angus Reid Institute which puts them up by eight.

That's a 14-point spread. It's a big one.

Maybe that shouldn't be too surprising. We're in the midst of summer, after all, and voting intentions aren't exactly locked-in.

These polls also were conducted using a variety of methodologies and the field dates don't all quite line up. The Nanos poll, for instance, was done over four weeks, while the other three were conducted over a week or less.

And this isn't even the first time we've seen significant variations between polls , and between these pollsters in particular.

So let's not worry about the top line numbers too much. On the whole, the polls point to a competitive, volatile race that probably favours the Conservatives .

Let's look instead at the trend lines — because that's what really matters at this stage.

The last time these four pollsters were all in the field at the same time was in early June. Since then, three have recorded gains for the Liberals ranging from one to five points, while the fourth (Ipsos) shows the Liberals holding steady. Similarly, three firms show the Conservatives dropping from one to four points, with Ipsos again showing a stable trend line.

There's no obvious pattern for the New Democrats or Greens in either direction.

This points to a race that's probably getting tighter, with the Liberals ticking up and the Conservatives ticking down. That's something we can say with a fair degree of certainty.

And if the numbers are still showing these wide variations the day before election day? That will be the time to freak out.

Tap here to go to the full poll tracker

Ask us

We want to know what YOU want to know.

One reader asked: I want to hear what specifically Andrew Scheer will do with regards to seeing the Trans Mountain pipeline completed. Will he sell it before completion, leaving it to fall back to private enterprise to complete it?

If there is one goal that both Prime Minister Justin Trudeau and Conservative Leader Andrew Scheer share, it's the completion of the Trans Mountain pipeline. Now that the pipeline has been approved, however, it's not clear how Scheer would take the file in a different direction should he become prime minister.

When it comes to approving pipelines in Canada and managing how those pipelines affect the natural environment, however, Scheer has a very different approach that hinges on repealing two recently passed pieces of legislation that matter to the oil industry.

The first law is the federal government's new environmental assessment legislation, which changes the rules for how natural resource projects are developed in Canada. Critics of the law, passed this June, say environmental restrictions contained within it make natural resource development in Canada too onerous and endanger their ability to draw the investment they need to see projects through to completion.

When Trudeau announced the government was buying the Trans Mountain pipeline to ensure it gets built, Scheer criticized the move, saying that the Liberals' stringent environmental legislation has created a climate where the only way to ensure large projects are built is for the federal government to take over.

Scheer has said that if he becomes prime minister he will repeal not only the environmental assessment law (which he calls the "No More Pipelines" law) but also the Liberals' tanker ban off the West Coast. Doing both would give industry more certainty, Scheer said, and ensure the federal government does not need to take a financial stake in projects to see them built.

Scheer also said he would "invoke federal jurisdiction when necessary" to ensure projects are built, but has not explained how he would use this authority with respect to Trans Mountain.

Scheer has proposed a national west-east energy corridor that would include a pipeline from Alberta and Saskatchewan to oil refineries in Quebec. But Quebec Premier François Legault has said there is no "social acceptability" for a pipeline in his province.

Under federal law (as Alberta Premier Jason Kenney has pointed out) the federal government has full jurisdiction when it comes to cross-provincial infrastructure like a pipeline, so any prime minister could force one through regardless of what the provinces say. Whether Scheer would be willing to go to war with Quebec over an energy corridor remains unclear.

-- Peter Zimonjic, Senior Writer, CBC Parliamentary Bureau

Have a question about the October election? About where the federal parties stand on a particular issue? Or about the facts of a key controversy on the federal scene? Email us your questions and we'll answer one in the next Canada Votes newsletter.

More from CBC News

>> Gerald Butts returns — and Trudeau's putting the band back together for October

His participation suggests the Liberals aren't all that worried about rehashing the SNC-Lavalin affair. Read more from Aaron Wherry here

>> Are there still NDP voters in a province that just passed a religious symbols law? Singh looks to find out

NDP leader tours Quebec heartland, vowing to lead opposition to secularism bill in Ottawa. Jonathan Montpetit has more

>> As Cambodia complains about trash exports, environmentalists urge Canada to ban practice

Groups want Canada to sign an amendment to the UN's Basel Convention. Catharine Tunney looks at the continuing controversy over garbage exports

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