What would the October election have looked like if based on PR

After I published my previous blogpost on December 9 I received a comment on Facebook asking what the results would have looked like using proportional representation.  Good question. I have now done just such a calculation, the results of which can be found below.

In the post I emphasized that the federal Liberals were effective in appealing to Ontario voters to "vote for a progressive government, not a progressive opposition". The key role of strategic/tactical voting in the election makes it clear that had proportional representation been in place, the voting shares would inevitably have differed from what actually took place. Knowledge on the part of voters  of the existence of PR would on its own certainly have produced a number of differences in the pattern of voting.

With those provisos, here are the seat results that would be produced by simply distributing seats based on a proportional voting system applied to the October 21 results.

As noted in the table I used a St. Lague PR voting calculation to calculate seat distribution using the vote shares produced in the October 21 election except in the northern territories. I used vote shares in each province and applied a 5% threshold rule - a party must have won at least 5% of the vote to be eligible to win seats (this excludes the PPC and independents such as Jody Wilson-Raybould). 

This is the same method used in Germany and New Zealand in their national elections for their list seats. However, they both use a mixed member system where half the seats are chosen in constituencies.  To simplify the calculus I assumed an all list system. My guess is that if Canada were ever to adopt PR it would be based on a mixed member system. However, assuming a proportional system were to emerge from the inevitably complicated and controversial reform process, the shares of seats we see in the table above would remain the about same.

The seat distribution seen here closely reflects the vote shares in the 2019 election at the national level.

Some observations about these results:

1. The largest single gain in seats would go to the NDP, the largest proportionate gain to the Greens.
2. The Liberals, Conservatives and Bloc all lose seats and seat shares.  The Liberals lose the most.
3. The logical coalition that would emerge here would be Liberal-NDP - the two parties would have 173 seats combined.

This is all of course completely hypothetical.  A PR system would likely produce more parties and multi-party coalitions.