Who loses most if there is a (mini) orange wave?

Jagmeet Singh is the most popular leader at the federal level. Many polls have shown this. His party, the NDP, is also up a good 3-4 points compared to the 2019 results and seems to have some momentum. Quite a contrast with the beginning of the last federal election when the NDP was fighting the Green around 10-12%.

It is therefore far from impossible to observe a mini orange wave. I say mini because this post isn't going to look at scenarios where the New Democrats were to increase as much as they did in 2011. I just want to see what happens if the NDP reaches 22, 24 or 26%. Would it affect the Conservatives or the Liberals more? All the graphs should be interpret in context of the current projections of this site.

First thing first, let's see if the NDP is becoming better at turning votes into seats.

At 19%, the NDP is projected to win around 30 seats. As you can see with the vertical points at 19 however, the NDP could win over 40 seats if efficient (lucky?) or as few as 20. It obviously depends on many things including where the NDP support is. But over 5,000 simulations, things even out. remember however that reality only happens once.

We can see that the average is picking up at around 22-24%. So the NDP is currently just below what we call 'la zone payante' in French. I guess we could say the 'touchdown zone' in English? Our electoral system usually creates such a zone at around 25% where parties start actually winning seats. The relationship is clearly not linear.

Who loses when the NDP increases? Well both but the Liberals are more affected.

It might be super obvious but the line is definitely steeper for the Liberals than for the Tories. The latter are losing 0.9 seats for every 1 percentage point increase of the NDP while the former are losing 1.9 seats (if I approximate with a linear effect).

Maybe a better visualization is to see what happens to the CPC and LPC seats when their leads (in percentages) over the NDP shrink. It's a more direct approach (in the graph above, it was possible for the NDP to be up by 1% but for the Liberals to also be up compared to 2019 for instance, thus mitigating the impact of the NDP's rise).

The Liberals are currently polling at 35% while the NDP is at 19%, so a lead of 16 points. For every point decrease in this gap, the Liberals are losing 3.7 seats. The Tories are only losing 2.7 seats whenever the gap shrinks. Again, I understand some of you will argue using the national numbers is meaningless and I should focus on the leads in Ontario and BC. That is fair but the simulations have correlations across provinces. So if the Liberals are dropping and the NDP gaining nationwide, it'll be the case in Ontario and BC as well.

And now maybe the weirdest graph: the number of seats for the CPC and LPC as a function of the number of seats for the NDP:

It is weird because the Conservatives have a very slightly positive relationship! That's right, the more seats the NDP wins in my simulations, the more seats the CPC wins as well. It took me a while to look deeper and understand what was happening.

The first part of the answer is what we have seen so far: the NDP has more races with the Liberals than the Tories. The second part is there are some seats that the Conservatives start winning when the NDP rises and the LPC is down. But there aren't as many seats the Liberals win if the NDP is taking votes from the Conservatives. So yes, vote splitting.

It's also a question of looking at correlations between only two variables when it's really a multivariate relationship. If you instead do a regression of the number of seats for the Conservatives over the number of seats for the NDP and Liberals, you get a negative relationship with both of these variables. So don't start thinking that the Tories necessarily love it when the NDP is gaining seats and rising in the polls. They like it to some extent if it means the NDP winning seats in Toronto, but they are a lot less happy when the NDP starts taking seats from the Tories in the West, including in BC.

So, overall, what have we learned? First of all, the NDP needs to likely be around 22% nationally in order to win 40 seats, one of their objectives. They can do it with a lower percentage of votes but higher efficiency of course. Second of all, a mini orange wave would likely hurt the Liberals significantly more than the Tories. It obviously depends where the NDP is rising (is it DT Toronto or BC) but, in average, it is pretty clear the NDP can hurt the Liberals more.