Please go take a look at the article at CBC.ca before reading any further. I've explained what I've done there, and also discussed some of the practical implications. But I thought I'd provide a little more detail here at the regional level for these seat estimates.
First, let's just start with the current polling averages as they were what all of my calculations were based on.
|Current polling averages|
Now, here is what these numbers would likely give in terms of seats.
The Conservatives win the most seats in British Columbia, despite trailing by three points there. The New Democrats take the bulk of Quebec's seats, despite being two points back of the Liberals.
Next, mixed-member proportional representation which, for the purposes of this analysis and easier comparison, I've simplified to proportional distribution of the 338 seats in the House (which is, in the end, the net result of the proposed system).
And finally, my estimates of the outcome of a preferential ballot, all else being equal (with MMP and especially with preferential balloting, the parties would change their behaviour - but let's assume they didn't).
Regionally, the Conservatives finish third in B.C. despite being second in support and the Liberals finish third in the Prairies despite being 13 points up on the NDP. The Liberals again finish second, but now by an even greater margin, in Quebec. And the Conservatives are shut out of Atlantic Canada though they are virtually even with the NDP.
But while preferential voting does not mimic first-ranked support, that does not necessarily make it non-representative.
Look at the EKOS polling I based these second-choice calculations upon. Combining first and second choice gives the Liberals a "theoretical ceiling" of 57%, against 54% for the NDP and 35% for the Conservatives. This is not all that different from Nanos Research's numbers on which parties Canadians would consider voting for: they were 56% for the Liberals and 43% apiece for the NDP and Conservatives in today's update from the firm. (This is actually an uptick for the Tories - over the last year the Liberals have averaged 53%, the NDP 43%, and the Conservatives 40% in Nanos's polling).
Food for thought, if this discussion ever becomes a serious proposal. I think a majority government by either the Liberals or the NDP would be required to get either of these changes implemented (though I wonder about the legitimacy of one party pushing through drastic electoral change). For the moment, at least, that does not seem like a probable outcome for 2015.