November 21st 2012: New BC model

Canadians from many provinces will likely have an election sooner than later. Among them, we can think of Québécois (who just elected a minority governement) as well as Ontarians (minority governement with a Premier who just resigned). However, the next election actually scheduled is the upcoming BC one, in May 2013. This is why I'm very pleased to publish the first projections using the new (and first) BC model.

Keep in mind this a version 1.0. In other words: very preliminary. Making accurate projections requires a lot of work. So far, I've used past election data to estimte regional coefficients and I found a way to introduced the (almost new) BC Conservative party. Nevertheless, a lot of fine tuning will be required before the election (and before I actually release the model to the public as a simulator).

If you want to know the details of the model (in particular, how I introduced the BC Conservatives despite a lack of data from the past elections), read further down. For now, I'll simply talk about the projections themselves.

I'm using the latest poll from Angus-Reid. Polling in BC has been relatively stable over the last year, especially for the NDP who has consistently enjoyed a healthy lead. The BC Liberals have experienced some ups and downs with the Conservtives, who even took second place for a couple of months. The Liberals are currently second though. But being second with a 25 points deficit isn't much to brag about.

Combine the very large lead of the NDP, the fact that Liberals and Conservtives are essentially splitting each other, and the electoral system, and you get the following projections:

NDP: 73 seats
BC Liberals: 10
BC Conservatives: 0
Green: 0
Independents: 2

The NDP would win by a landslide. At this point, and except if all polls are completely wrong, the NDP would not only retake power after 3 liberals governements, but they would hold a comfortable majority. The BC Liberals would fall hard and most of the 10 seats they are currently projected to win aren't safe. The Conservatives would come close a couple of times, but ultimtely would likely fall short. They need to go back over the 20% mark in order to win seats. Please remember that these are seats projections without much uncertainty added. By the time of the election, I'll also provide an idea of the seats range for each party. So don't take the 0 seat for the Conservatives as clear evidence that this party wouldn't elect a single MLA. It simply means that this party isn't currently in a position of becoming even the official opposition. As for the two independents (in Detal South and Prince River North), I'm simply assuming they stay stable from the past election; I'll most likely revise this assumption later).


Ok if you're still reading, it means you're interested in the details of the methodology. As usual, I used past elections in order to estimate regional coefficients in order to transpose the provincial swing into riding-level ones. BC is a little bit annoying because they changed their electoral map between 2005 and 2009. Not only that, but a complete transposition of the results (like the 2005 results with the 2009 map) isn't even possible because the boundaries of the voting reas have changed as well. For this reason and the fact that the provincial swings between 2005 and 2009 were very small, I only used the 2001 and 2005 elections to estimate the coefficients. I could use the 2009 as well by working at the regional level, but as I've said, the swings were so small that it wouldn't influence the coefficients very much. Unfortunately, while models from this site usually include an incumbency effect, it isn't currently the case in the BC model. The reason is because after the 2001 election, the Liberals had all but two seats. So it's almost impossible to disentangle the regional effects from the incumbency one (in some regions, the Liberals had all the seats, making the estimation impossible). An incumbency effect could be estimated using 2005-2009 but again, different maps, so no actual riding-level swing to use.

One tricky part for the upcoming election is to include the BC Conservatives. While this party technically existed back in 2005 and 2009, they were at that time a very marginal party. It's only recently that they have enjoyed polling well into the high 10's or low 20's. Therefore, past elections won't be very useful in order to help us project this party. However, the one evidence we have from polls is that the Conservatives are taking their support almost entirely to the Liberals (just look at the graph in the Angus-Reid polls to see that). Therefore, I proceed this way: first, I use the coefficients to project the NDP, Green and Liberals. Then, the Conservatives take a specific percentage of the Liberal vote. For instance, if the Conservatives are at 20%, they would take 20/45 of the Liberals votes from the last election (45% being the result for the liberals in 2009). There is thus no regional specific coefficient at the moment.

I spent the last couple of weeks trying to improve the methodology for every model. In particular, on top of regional and incumbency effects, I want to be able to account for where the votes is coming from. Specifically, if the Liberals lose votes to the NDP, it is different than when they lose votes to the Conservatives. The regional variation won't be the same. It's the same as what happened in Quebec at the federal level. When the Bloc was losing votes to the Conservatives, the Bloc was decreasing a lot in Quebec city. On the other hand, when the Bloc was losing votes to the NDP, they were pretty stable in Quebec city (where the NDP wasn't increasing as well as elesewhere in Quebec). It's the same logic applied here. The regional coefficients estimted from 2001 and 2005 show us the regional variations that would occur if the Liberals were decreasing and the NDP increasing. But the Liberals are mostly losing votes to the Conservatives this time around. So it's reasonable to expect the swings to look differents than if the BC Liberals were losing 20 points to the NDP only. Therefore, I account for this fact in the BC model. Namely, the liberal swing of -20 points is split between a loss of 6-7 points to the NDP and a loss of the remaining points to the Conservatives. The 6-7 Lib/NDP swing is thus transposed using the coefficients, while the remaining 13-14 points Lib/Conservatives swing is transposed using the assumption that the Conservatives are taking the same share of liberal votes everywhere. Of course, it'd be nice if the share of lib votes taken by the Conservatives was regionally adjusted, but for now, it's hard to really estimate this without pure guessing.

I'll keep working on the model. You cn also expect the full details os the new federal model soon. Then, it's gonna be time to start working on models for Quebec and Ontrio.

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