The complete preliminary results are in:
LIB - 70 (41.5%)
PQ - 30 (25.4%)
CAQ - 22 (23.1%)
QS - 3 (7.6%)
With a uniform swing from last election, the seat distribution would have been LIB 76, PQ 35, CAQ 12, QS 2. Thus, from a projection modeling standpoint, the big news of this election is that the CAQ vote got much more efficient, allowing it to win 10 extra seats.
Consider the following:
- The CAQ gained 8 of the 9 ridings where it lost by less than 8% to the PQ in 2012 and that the Liberals did not win this time. The only exception was Rousseau, where outgoing Finance Minister Marceau held on. The only other CAQ gain was Masson, next door to Legault's riding. Therefore, it's as if the CAQ gained 8% on the PQ, even though the actual swing was only 2.6% (from a 4.9% gap to a 2.3% gap).
- The 5 CAQ losses to the Liberals were exactly the 5 ridings that it won by less than 8% over the Liberals in 2012. (The only other CAQ loss was Saint-Jérôme, where star CAQ incumbent Jacques Duchesnau, who did not run, was replaced by PQ star Pierre-Karl Péladeau.) Therefore, it's as it the CAQ fell by 8% relative to the Liberals, even though the actual swing was 14.3% (from a 4.1% gap to a 18.4% gap).
Taken together, the increased efficiency of the CAQ vote was worth a whopping 6% to the party! That is, if swing were uniform, the CAQ would have had to get about 4% more, equally from the Liberals and the PQ, to achieve its seat count of 22.
The increased efficiency of the CAQ vote is evidence that people do vote strategically when they can. It was hard to do in 2012 because both the CAQ and the electoral map were new. This time, however, potential CAQ voters had some guidance as to whether it was worth voting for Legault's party. This might have made the CAQ lose votes where it is uncompetitive, and gain votes where it is the main alternative to the PQ.
Of course, one could also attribute the increased CAQ vote efficiency to the CAQ leading a more focused campaign based on data from 2012. However, the PQ also had a very focused campaign, which did not prevent them from doing poorly where it focused.
How about the Liberal/PQ vote efficiency? It basically did not change compared to 2012. The PQ to Liberal swing was 16.9%, and there were 16 ridings that the PQ won by less than 16.9% over the Liberals in 2012 and that the CAQ did not carry this time. Of those, the Liberals won 14, the only exceptions being Bonaventure and Taschereau, which were both close. The only other Liberal gain from the PQ was Roberval, the riding of Premier-elect Couillard. Thus, the basic uniform swing model would have, as is often the case, done a fantastic job predicting seat changes between the two main parties.