A week is a long time in politics: 14 years of Canadian polling data

This post’s title is a saying often attributed to Harold Wilson, the British Labour Prime Minister who served in the 1960’s and ‘70s.  Although the origins of the quote are unclear -- Wilson did not recall ever saying it -- the meaning is not: fortunes in politics are subject to rapid rises and falls.  This is, no doubt, very true in Canada.

In this first post, I want to show you a straightforward time series of Canadian political party support over the last 14 years.  To my knowledge, it is the longest single time series of Canadian political polls. 

This period coincides with the creation of a united Conservative party, the secular decline of Quebec separatism, the “coalition crisis” of 2008, the “Orange crush” collapse of the Liberal vote in 2011, and the subsequent Liberal majority in 2015.  It spans four Liberal leaders (Martin, Dion, Ignatieff, and Trudeau), three NDP leaders (Layton, Mulcair, and Singh), and two Conservatives (Harper and Scheer). 

With all that laid out, here are some quick high-level points that emerge from this national picture:

  • Changes in national political support have “fat tails”: party support can appear relatively stable for long periods of time before suddenly shifting.  To put this another way, political support is subject to “Black Swan events” where the magnitude of shifting support can dwarf any smaller variations previously observed.  A clear example of this is the rise of the NDP in the 2011 election: if you look at the data leading up to the 2011 election, it would be nigh impossible to predict the NDP surge, which is well above any historic highs they ever achieved.  In fact, it appears as if the Liberals and NDP quite literally swap 15 points of support in a single week!  Which leads to the second point…
  • Election campaigns matter: major shifts in the political environment coincide with election campaigns.  Whether it’s the Conservatives overtaking the Liberals (2006), the NDP and Liberals swapping (2011), or the Liberals overtaking both the Conservatives and NDP (2016), there are many examples where support for the parties changes radically from the start to end of a campaign.
  • Party leadership conventions move polls: Just eye-balling the chart shows that new leaders often get a bounce when they’re nominated.  Dion saw a ~5ppt bump, Ignatieff was probably closer to 10ppt, Mulcair got ~5ppt, and Trudeau saw a sustained ~10ppt step-up in support.  Although it might be too soon to tell, Scheer and Singh appear to have much smaller bumps in comparison.

With all that being said, anyone familiar with Canadian politics knows that the national support for a party is actually a rather meaningless number.  The actual outcome of the election is determined by the individual electoral districts (like the US electoral college).  For instance, the Bloc Quebecois has little support nationally yet they play a disproportionate role in our politics due to their regional concentration.  Similarly, the Green party is a national irrelevance because their support is so dispersed. 

In short, what’s probably more interesting is what this picture doesn’t show: our political system is highly regional and this can have profound effects on electoral outcomes.   As a continuing series of posts on this blog, I hope to lay out some of my thoughts on how our election system can be modeled.

How to read the chart:

  • Each party is represented by a colour: Liberals are red, Conservatives are blue, the NDP is orange, the Greens are green (surprise!), and the Bloc is purple
  • Each of the lightly coloured dots represents a single poll published by a polling agency
  • The coloured lines and bands represent a smoothed average of these polls over time (using a Loess regression.  I’ll probably explain how this works in a future post.  For now, I want to avoid too much maths)

Sources: Over the years, I have manually tracked publicly reported polls.  In recent years, I have started also relying on Wikipedia to make sure I have not missed any polls.  You can easily access the Wikipedia data here.