In the black-and-white world of our first-past-the-post system, the byelections held on Monday can be summed up very simply: the Conservatives won and the opposition parties lost.

Although one should not make too much of the results, the shifts in vote share, taken in tandem with other byelection results and public opinion polling, reveal that some losses are easier to take than others.

The Conservatives won both ridings up for grabs Monday with healthy shares of the vote, taking 49 per cent in Ontario's Whitby-Oshawa and 63 per cent in Alberta's Yellowhead. The Liberals finished a strong second in the former with 41 per cent, while garnering 20 per cent of the vote in the latter, the party's best performance there since 1993.

The New Democrats had no silver linings to find in the results, however, taking 10 per cent in Yellowhead and just eight per cent in Whitby-Oshawa, their lowest results in both since 2000.

While there were unique factors at play in both ridings — Yellowhead had a meagre turnout of just 16 per cent, and Whitby-Oshawa was the riding of former finance minister Jim Flaherty — the results align with trends that have been exhibited in other recent byelections.

The Liberals gained significantly in their share of the vote, almost tripling it in Whitby-Oshawa and increasing it nearly seven-fold in Yellowhead. The party picked up an average of 21.9 points in the two ridings, better than the average 18.6-point gain the party made in other byelections since Justin Trudeau became leader in April 2013.

The Conservatives dropped an average of 11.8 points, virtually identical to their average loss in other recent byelections. But that drop came from a higher share of the vote to begin with — the party actually decreased by a lower proportion on Monday than it has elsewhere since the last federal election.

For the New Democrats, the loss of an average of 8.9 points was worse than the party's previous byelection performances since 2011 (an average drop of 6.3 points).

Liberal numbers softening

In addition to the byelection results falling in line with other contests that have occurred since the last federal vote, they also align with what public opinion polls have been suggesting — for the most part, at least.

The Liberals have been ahead in the polls since Trudeau became leader, and their impressive byelection gains seem to confirm those numbers at the ballot box. Both the Conservatives and New Democrats are polling well below the levels of support they had in 2011, and have accordingly also experienced a drop in support in byelections.

But the Liberals should not get carried away by the gains they made on Monday. Nationally, their numbers appear to be weakening.

The party currently enjoys the support of about 35 per cent of Canadians, according to a weighted average of the latest polls. That is down from the 39 per cent the party had in early September, before parliamentarians returned from their summer break.

There have also been signs that Trudeau's own personal support is faltering. The Nanos Party Power Index poll released last week, put him behind Stephen Harper on the question of who Canadians preferred for prime minister for the first time since July.

By the same token, the Conservatives should not take too much comfort in their respectable byelection results.

Though their position relative to the Liberals has improved, the Conservatives are still mired at 30 per cent support countrywide, and trail the Liberals by seven points in Ontario. Despite the win in Whitby-Oshawa, if a similar Conservative-to-Liberal swing occurred provincewide, Tory ranks in Ontario would be decimated.

For the New Democrats, the result in Whitby-Oshawa confirms the poor polling results the party has been putting up in Ontario. At just 18 per cent support in the polls there, the NDP is back to the level of support it had in the province before the 2011 breakthrough. The NDP's drop in Yellowhead was modest, backing up the party's steady support levels in Alberta. However, the NDP won just one seat in the province in 2011.

While the byelection results do not necessarily foreshadow what will happen in next year's general election, they do corroborate to a large degree what polls have been suggesting and give an indication of where sentiment lies today.

That suggests both the Conservatives and NDP have some catching up to do. But for Stephen Harper, the victories in Yellowhead and Whitby-Oshawa at least provide some encouragement.


ThreeHundredEight.com's polling averages include all polls that have been published and are weighted by sample size, date, and the track record of the polling firm. Methodology, sample size and margin of error if one can be stated vary from survey to survey and have not been individually verified. See here to read more about the methodology.