Franois Legault's CAQ has the edge as Quebec provincial election approaches

The polls sayFranois Legault'sCoalition Avenir Qubec is in a strong position to defeat Philippe Couillard's Liberals in the upcoming provincial election.

But there arenearly eight weeks to get through before Quebecers actually cast their ballots. Where they stand today is not necessarily where they'll be when they head into the voting booths on Oct. 1 and the best way to follow the ebbs and flows of the campaign will be the CBC's Quebec Poll Tracker, which launches today.

• Quebec Poll Tracker: Check out the latest projections
• Full coverage of the Quebec election from CBC News

With 34.8 per cent current support in the Poll Tracker an aggregation of all publicly available polls weighted by date, sample size and pollsters' track records the CAQholds a five-point lead over the Liberals, who followwith 29.7 per cent.

The Parti Qubcois under Jean-Franois Lise trails at a distance in third place, with just 17 per cent closer to Qubec Solidaire's 10.7 per cent support than it isto the second-place Liberals.

Another 7.8 per cent of Quebecers say they will vote for a different party, such as the provincial Conservatives, New Democrats or Greens.

While that five-point edge over the Liberals is hardly dramatic (the Liberals won the 2014 provincial election by a margin of 16 points), it's still enough for the CAQ to win a majority if these numbers are replicated on election night.

The Poll Tracker estimates the CAQ would win between 60 and 85 seats with these levels of support, comfortably straddling the 63-seat threshold needed for a majority. The Liberals would win between 27 and 53 seats, with the PQ scraping by with between one and 25 seats.

Qubec Solidaire is competitive in as many as 10 ridings, though it's only projected to be in the best position towinfive of them. The PQ is the favourite in just four ridings.

Francophone vote boosting CAQ

The CAQenjoys an advantage in the seat count far beyond its lead in the popular vote thanks to its support among francophone voters. While the gap between the CAQ and Liberals is only five points provincewide, Legault's party is 18 points ahead of the Liberals among francophones.

The CAQ has 40.2 per cent support among francophones, followed by the Liberals at 22 per cent and the PQ at 19.5 per cent. Among non-francophones, the Liberals dominate (as they usually do) with 68.3 per cent support. The CAQ follows at a distance with 10.2 per cent support among non-francophones.

While that does mean the Liberals have a solid base of seats, their deficit among francophone voters limits their competitiveness in the seat count. Accordingly, the Poll Tracker estimates that the CAQ would have a 96 per cent chance of winning the most seats if an election were held today; the Liberals simply don't have enough support among francophones to close that gap.

Campaigns matter and polls show why

But campaigns can change things and the Quebec Poll Tracker will measure how opinions evolve over the next eight weeks. By combining all of the individual polls published over the course of the campaign, the Poll Tracker will focuson trends that can be identified across different pollsters and drill down into the regional and linguistic differences that decide elections in Quebec.

It's a tool that has proved its worth in other provincial elections particularly the recent campaign in Ontario. That election began with Doug Ford's Progressive Conservatives enjoying a commanding lead, and Kathleen Wynne's governing Liberals and Andrea Horwath's New Democrats vying for runner-up status. By the end of the campaign, Ford's victory was no longer assured after the NDP made historic gains though the New Democrats came up short in the final days.

The polls helped tell that story. But the Poll Tracker also helped identify the problemthe New Democratsfaced in turning those poll numbers intoseats: the inefficient distribution of their vote. That's where the seat projection came in handy and that's likely to be the case again in Quebec.

In 1998, the Liberals under Jean Charest won more votes than Lucien Bouchard's Parti Qubcois by a margin of 43.6 to 42.9 per cent but the PQ still secured a comfortable majority government. Because of the significant linguistic divisionin support, the headline poll numbers in Quebec never tell the entire story.

• Complete Quebec Poll Tracker methodology

But there's always a degree of uncertainty when it comes to projecting election outcomes. That's why the Poll Tracker puts an emphasis on what are called 'confidence intervals'. By taking into account past performances of polls and the projection model itself, it's possible to estimate the range of plausibleoutcomes given the information available.

In the end, voters can be unpredictable and do unexpected things. But the broad strokes of an election can be painted accurately by the polls, providing context for much of what goes on between the start of a campaign and the day ballots are finally cast.

The CAQ starts this campaign with an advantage. We'll soon find out if they can keep it.