The election isn't officially started yet, but we're already talking about a possible coalition between the LPC and NDP (and, to a lesser extent, the Bloc). This post is not intended to promote such coalition. Nor do I want to argue whether such coalition is legitimate or a good idea. My objective here is simply to show how many seats such a coalition could grab. And I'm well aware that the scenario studied here is highly unlikely to happen in Canada. So don't fall on me for that lol See that as an academic exercise, nothing more.
I'm talking here about a coalition PRE-election, where the NDP and LPC officially announced that they would do one. If such a situation should occur, then I believe the two parties should actually "exchange" candidates in some key ridings. Indeed, it is the case that in some ridings, the CPC can win, but the total sum of votes for LPC and NDP is actually greater. When it is the case AND those two parties want to do a coalition, then they should be logical and leave only one candidate. That would avoid a split of the "coalition votes". But of course, to really forecast what would happen in such circumstances, we need to take into account the second choices of the voters. Indeed, it is obvious that in the event that the NDP removes its candidate, not all voters will follow the order and give their vote to the Liberals. Some will simply not vote, while other will vote for another party, including the Conservatives.
So here are the details of this experiment:
- I'm using the latest projections, based on the average of most recent polls.
- I'm using the second choices as given in one of the latest Ekos poll.
- I'm assuming that the coalition would do such a candidate swap only in the ridings where they can potentially beat the Conservatives. Specifically, it has to be the case that CPC is first, and LPC+NDP is greater than CPC. As you'll see, the number of ridings currently in this situation is not that big.
- The "coalition" would remove the candidate from the party that is currently third. In other words, if the Tories are first, the Liberals second and the NDP third, then the NDP candidate would have to go.
- When one candidate is removed, I'm using the second choices of the voters of this party and redistribute the votes.
This redistribution requires some explanations and assumptions. First of all, I'm well aware that some voters would switch even though their first choice is still technically available. For instance, in our previous example, we could expect some Liberal voters to actually change their votes simply because they don't want a coalition with the NDP. That could happen to some voters that are exactly between the Tories and the Liberals. Here, I'm assuming that this isn't the case. This introduces a bias, but hopefully it will be canceled out by the next assumption. The second choices are biased as well. Indeed, it is one thing to not name the Liberals as your second choices when you are a NDP voters (possibly, you don't have a second choice, which happens in around 30% of the cases), but it's another thing to be told by the NDP to vote LPC. We can imagine that some voters that didn't have the Liberals as second choice would still switch their votes, simply because they understand the whole principle of the coalition and the candidates exchange. I don't model that. So at the end, I have two assumptions who both introduce a bias, but in the opposite direction. In the future, I could try to "play" with those assumption and see what it would change (or even better: maybe we'll have one pollster asking specifically how many people would switch or not, in the event of a coalition).
So, enough about the technicalities, let's see if such a deal could actually benefit the Liberals and NDP. Based on the current projections (they are a little bit different from the ones displayed on the right because I added the latest Ipsos poll), here is what such a deal would change:
Number of ridings where the LPC+NDP>CPC: 34
| seats | actual | coalition |
| CPC | 153 | 148 |
| LPC | 72 | 74 |
| NDP | 32 | 35 |
| Green | 0 | 0 |
| Bloc | 51 | 51 |
So, out of the total of 34 ridings where the coalition votes is higher, such a deal would only take 5 seats away from the Conservatives. The main reason? Well it is the retention rate. Specifically, only 32% of NDP voters have the Liberals as second choice (and 33% of LPC have the NDP). Those numbers are not high enough to warrant such a deal pre-election. However, let me say two things.
1) The current projections are very favourable to the Tories. We'll see what happens during the campaign. Such an exercisee would give different results if the Liberals go up and the Tories go down. For instance, if we were to go back to the levels of support of 2006, you would see that such a coalition would be much more effective.
2) As I've said, maybe one of my assumptions is to harsh. Do you really think that only 32% of the NDP voters would switch to the Liberals, while 23% would prefer to vote for the Green and 25% would simply not vote? I have a hard time believing that. Polls usually showed that the NDP voters were quite pro-coalition, back in 2008 (but in the same time, as I've said, some Liberals voters could be scared off as well). So I might adjust those assumptions. In my simulations, it seems that the coalition becomes effective when the retention rate is at 45% or more.
In any case, as I've said, this is simply meant as an exercise. I will repeat it or modify it during the campaign. In the mean time, let me know what you think. By the way, you might think that "stealing" 5 seats away from the Tories is not that big of a deal, but if those 5 seats are the difference between a majority and minority, it could well be important!
