Thursday, July 21, 2011

Ontario seat ranges and margins

Prompted by reader comments, I've taken a deeper look at the Ontario projection. By looking at close races, the projection can give some plausible seat ranges. I've also looked at what kind of margins are needed to prevent the Progressive Conservatives from forming a majority government and what's needed to install the New Democrats as the Official Opposition.

I will update the seat ranges with each new projection. They are established by identifying ridings in which the margin of victory is less than 5%. This will be a good guide for what is possible, as the projection is subject to the margins of error of the polls used as well as the unpredictable nature of local politics.

The following seat chart shows the number of seats in which each party is leading or trailing by less than 5%.

A lot of the races, even with a 10-point Tory lead, are toss-ups.

The Progressive Conservatives are leading by less than 5% in 13 races, while the Liberals are leading by less than 5% in 10 ridings. In other words, 23 of the 107 seats in the province are being decided by less than 5% in the projection. The 18 seats in which the NDP leads are all relatively safe.

The PCs are trailing by 5% in nine ridings, the Liberals in 13 ridings, and the New Democrats in two ridings.

For the Progressive Conservatives, that means that they could win as few as 48 seats if all of the ridings in which they lead by less than 5% went the other way. That is still likely to give them a plurality, however, and with the nine ridings in which they trail by less than 5% going to the Tories they could win as many as 70 seats.

For the Liberals, it is boom or bust. If they win all of the races in which they trail by less than 5%, they could win 41 seats. This would still put them behind the Tories but probably allow them to govern with the help of the NDP. But if things go badly for the Liberals, they could be reduced to only 18 seats and probably place third in the province.

There is less opportunity for growth for the NDP, with their high seat range being 20. That is still double what they currently have, however.

With a lead of 10 points, the Tories are comfortably in majority territory. But what kind of lead do they need to win 54 of the province's 107 seats?

Assuming the New Democrats are at 19.9% support, a gap as low as eight points between the PCs and the Liberals would still deliver 57 seats to the Tories. But if the margin is reduced to seven points, the PCs win only 54 seats - the bare minimum for a majority. At a gap of six points, the Tories win 53 seats and a minority government.

But what of the NDP's chances to supplant the Liberals as the Official Opposition, as they have done at the federal level?

That would require quite a bit more movement. Assuming the Progressive Conservatives remain at 41.3% support, the Liberals would still win 27 seats to the NDP's 18 with a gap of 10 points separating the two parties. The Liberals are still in a comfortable position if that lead drops to six points - this would deliver 23 seats to the Liberals and 19 to the NDP, with the PCs at 65.

However, if the gap between the Liberals and the NDP drops to five points, the Liberals win only 21 seats in the projection to 20 for the NDP. And at a gap of four points, the New Democrats win 21 seats, the Liberals 17, and the PCs 69.

We're a long way from either of these two scenarios playing out. But the seat ranges and these margin tests show how much is still up for grabs in Ontario.

UPDATE: After receiving so many requests for individual riding projections, I decided in the end to include the riding projections on the site. I invite you to read the disclaimer with the riding projections.