The opposition parties in Ontario have good reason to complain about the scheduling of today's by-elections in the middle of the summer. An analysis of recent by-elections in the province shows that incumbent parties benefits when voter turnout is down.
There have been 28 by-elections held in Ontario since 1996. Of those, the incumbent party has retained 20 of them, while eight have been won by a challenger. The average turnout in those 20 seats held by the incumbent party over that time has been 36 per cent, while in ridings lost by the incumbent turnout has averaged 40.3 per cent.
Compared to the preceding general election, turnout in ridings where the incumbent party won the by-election dropped by an average of 21.5 points, or 38 per cent. In ridings where the incumbent was defeated, turnout dropped by only 16.7 points, or about 29 per cent. In other words, when turnout is particularly anemic the incumbent tends to get better results.
The most recent federal by-election shows how high turnout can hurt the incumbent. In Labrador, where Peter Penashue was defeated by Liberal Yvonne Jones, turnout in the by-election actually increased from the 2011 general election. Mr. Penashue was defeated with only a drop of about 700 votes, while the majority of Liberal gains were likely from people who had not voted in 2011.
It is impossible to know for certain, however, if low turnout is the cause of incumbent victories. Where the outcome is considered a foregone conclusion for the popular incumbent party, for example, voters simply might not bother to show-up. But nevertheless, if turnout is low in today's by-election the Liberals may be able to hold on to more seats than they would otherwise.
But the conventional wisdom that by-elections are bad for governments is not particularly wise. Of the last 14 provincial by-elections in Ontario going back to 1996 in which a government-held seat was at stake, only five of them were won by opposition parties. That means that the Liberals should have a roughly 2 to 1 shot of winning any by-election just based on history alone, and at least three of the five seats up for grabs today.
Turnout has the potential to give smaller parties a chance to make a big impact if they hold on to their voters and supporters of other parties fail to cast their ballots. The federal Green Party has been especially successful in this regard, taking more than 25 per cent of the vote in the Calgary Centre by-election of 2012 despite that not representing enough raw votes to have been able to vault them out of fourth place in the 2011 federal election. In the Victoria by-election that occurred on the same day, the Greens were able to double their vote and put a scare into the New Democrats, who lost half of theirs when turnout dropped from 69 to 44 per cent. And in London North Centre in 2006, the Greens were able to almost triple their vote and finish second to the Liberals. Here again, their raw vote haul would not have been enough to move them out of fourth in the previous general election, but with lower turnout they were able to be much more competitive.
But the most memorable recent by-election in Ontario provincial politics demonstrated how turnout is not always a factor in deciding the outcome. In Kitchener-Waterloo in 2012, turnout hardly changed from that of the 2011 general election. But since the New Democrats more than doubled their vote, taking away from both the Progressive Conservatives and the Liberals, they were able to wrestle away the riding. This was a case of a true swing in voting intentions not attributable to turnout. Might any of today's by-elections show something similar?
Éric Grenier writes about politics and polls at ThreeHundredEight.com .