Canada 2019: Results and a good night for the Seat Product Model

Add Canada 2019 to the set of plurality reversals. As anticipated before the election, the two largest parties each ended up with around one third of the vote. This is the lowest vote percentage for a governing party in Canada ever, I believe. The seats are somewhat less close than the CBC’s Poll Tracker estimated they would be. Instead of 133 seats to 123, the seats split 157 to 121. The Liberals are indeed that largest seat-winner, despite trailing the Conservatives in votes percentage, 34.4 – 33.1.

The NDP was either overestimated by polls or, more likely, suffered some late strategic defection. Instead of the near 19% of the vote in the final Poll Tracker, the party ended up with only 15.9%. More importantly, its seats stand at only 24, well below where estimates late in the campaign had them (per the CBC Poll Tracker).

As excepted the BQ had a good night, with 32 seats. The Greens picked up one new seat to augment the two they already held. The new seat is Fredricton, New Brunswick, whereas the other two are both on Vancouver Island.

In what I will call the two best pieces of news form the night (other than there being no single-party majority), the People’s Party crashed and burned, winning only 1.6% and seeing its leader lose his seat. That and the fact that Jody Wilson-Raybould, the former Attorney General who was kicked out of the Liberal caucus, retained her seat, Vancouver-Granville, as an independent.

 

Anomalous FPTP

I will certainly use this result often as a demonstration of how the first-past-the-post (FPTP) system can produce strange results.

Not only the plurality reversal for the top two, but the differential treatment of the next three parties, show anomalies of the sort that are inherent to FPTP. The BQ is only somewhat larger in votes than the Green Party, but will have more than ten times the number of seats. Under FPTP, it is good to have efficient regional distribution of support, and getting all your votes in one province, where you perform exceptionally well, is really efficient. The Greens, on the other hand, gained in almost all provinces, but it was good enough to add only one seat.

The NDP’s situation is one of a quite strong third party, but also inefficient regional distribution: 7.1% of the seats on 16% of the votes is a punishing result, but nothing at all unexpected, given the electoral system.

For that matter, the plurality reversal is itself a signal of the problem of inefficient vote distribution. The Conservative Party mostly gained votes where they could not help the party win seats, whereas the Liberals were much more successful winning close contests.

In his victory speech, PM Justin Trudeau was bold enough to use the M-word (mandate), but this most certainly is not one. For the moment, he can be pretty happy he broke that promise on 2015 being the last FPTP election. His party remains in position to form the government, and has a substantial seat bonus. The advantage ratio (%seats/%seats) is 1.40. (How does that compare with past elections? Click to see.)

Canada would be well served by at least some degree of proportionality. In fact, so would the Conservatives, given their tendency to run up margins where they are already strong. (Note that they are only barely over-represented in seats, with 35.8%.) However, this result is unlikely to advance the cause of reform, as the Liberals’ position–46% of the seats and a 36-seat (more than ten percentage point) edge over the runner-up–looks quite solid.

The other reason the country could really use electoral reform is the map. There is no Liberal red to be seen from central Ontario westward, except around Vancouver (and two northern territories). The party lost some of its ministers’ reelection bids in Alberta and Saskatchewan. With even a minimally proportional system, the situation of a governing party without members of its caucus in nearly every province would not happen.

While a PR system would be beneficial, the country is stuck with FPTP at least for now. So how did this result compare to what we should expect from the electoral system actually in use?

 

The Seat Product Model and the outcome

The Seat Product Model (SPM) performed better than the CBC Poll Tracker’s seat estimator. For an assembly of 338 and districts with magnitude of 1, we should expect the largest party to have, on average, 48.3% of the seats, which would be 163 seats. So the actual result (46.4%) misses the expectation by 6 seats, or 1.78 percentage points (compared to the a 20-plus, or 6 percentage point, miss by the Poll Tracker).

Of course, the SPM has one advantage in its favor: it does not “know” that the seat-winning party would have under 33.3% of the vote, whereas the Poll Tracker must work with this expectation (and, as it turned out, reality). In fact, when a party wins 48.3% of the seats, the formulas of SPM (collected in Table 9.2 of Votes from Seats) expect it to have won 43.3% of the votes. (Theoretically, we do not expect the SPM to perform as well with votes as with the seats that are at its core; but in Votes from Seats, we show that, on average, it performs about equally as well with both.) The Liberals underperformed this expectation by more than ten percentage points! The voters genuinely voted for something their electoral system could not deliver, even if the system indeed delivered what should be expected solely on institutional grounds.

In terms of the effective number of seat-winning parties (NS), the actual result was 2.79. This is slightly higher than the SPM expectation, which is 2.64. The miss is minor, with a result only 1.057 times expectation.

On the other hand, the effective number of vote-earning parties (NV) was 3.79. The SPM expects 3.04. Let me pause and emphasize that point. Because Canada uses FPTP in a 338-seat assembly, we should expect the votes to resemble a “three-party system” and not the two-party system that all the conventional “Duvergerian” wisdom claims. If we calculated expected Nbased on the known NS=2.79, we would expect NV=3.17. However, neither the SPM nor Duverger’s “law” expects that the largest party nationwide should have only around a third of the votes. That is the really remarkable thing about this outcome.

 

The district level

At the district level, there were numerous non-Duvergerian outcomes, as would be expected with the known distribution of nationwide votes among parties. According to an extension of the SPM (in a forthcoming book chapter), we should expect the effective number of vote-earning parties at the average district (N’V) to be 1.59 times the square root of the nationwide NS. That would be 2.66. It will be a while before I am able to calculate what it actually was, but it would not surprise me if it was a fair bit higher than that. But, again, let me pause and say that a Duvergerian two-party competition at the district level is NOT to be expected, given both the nationwide electoral system and the actual aggregate seat outcome. (If we went off expected nationwide NS, instead of the known outcome, the district-level mean still would be predicted to be 2.58; see Chapter 10 of Votes from Seats.) Canadian elections of the past several decades have tended to conform closely to this expectation for district-level N’V.

The country does not tend to have two-party contests at district level, nor should it (when we have the Seat Product Model to guide our expectations). In other words, voters do not tend to vote in order to “coordinate” their district outcome around the two most viable candidates. They tend to vote more towards their expectation (or desire) about what the nationwide parliamentary outcome will be. This is so even in Quebec where, in this election, many Francophone voters returned to the regional party, the Bloc Québécois. Quebec has numerous district contests that feature three or four viable parties.

So if your image of Canada’s party system is that in Quebec districts it is BQ vs. Liberal, with other parties barely registering, while elsewhere it is Liberal vs. Conservative, except where it is one of those vs. NDP, it is well past time to update. Canada does not have nationwide multiparty politics because it has separate regional two-party systems (as many folks, even political scientists, seem to believe). Canada has district-level multipartism because it has nationwide multipartism. (See Richard Johnston’s outstanding book for a rich “analytic history” that supports this point.) And this may be even more true in the one province in which there is (again) a strong regional party. Consider the aggregate provincial outcome in terms of vote percentages in Quebec: Liberal 34.2% (slightly higher than nationwide), BQ 32.5%, Conservative 16.0%, NDP 10.7%, Green 4.5%. This gives a provincial-level NV of 3.82, a bit higher than nationwide.

I will offer a few striking examples of multiparty contests at district level, just to illustrate the point. The new Green Party MP from Fredericton, Jenica Atwin, won 32.8% of the vote. The Conservative had 31.1%, the Liberal 27.3%, and the NDP 6.0%. There may indeed have been strategic voting happening here, with some NDP voters–the party had 9.9% in 2015–switching to Atwin to stop the Conservative (and perhaps some who don’t like the Greens boosting the Liberal). But the outcome here is N’V=3.53!

The change from 2015 in Fredericton is really striking, as the Liberal candidate was an incumbent who had won 49.3% in 2015 (against 28.4% for the Conservative, meaning this party gained a little here in 2019). Clearly many Liberals defected from their party to the Green following that party’s success, including a local win, in the recent provincial election. In doing so they only narrowly avoided the serious “coordination failure” that would have been a Conservative win.

Another Green MP, the reelected Paul Manly in Nanaimo-Ladysmith, won 34.5%. This was actually a pretty clear victory despite being barely over a third of the vote; Manly had been elected in a by-election this past May with 37.3%. The runner-up Conservative had only 25.9% in the general election contest, the NDP 23.7%, Liberal 13.6%. N’V=3.83!

Wilson-Raybould’s win in Vancouver-Granville as an independent was also with under a third of the vote. She had 32.3%, beating the Liberal’s candidate (26.6%) and the Conservatives’ (22.1%). The NDP candidate had 13.1%. The Greens, who tried to recruit Wilson-Raybould to be their candidate, put up their own against her, who got 5.0%. It should be noted that the NDP candidate in this riding last time won 26.9%, so it would appear there was ample strategic voting here in Wilson-Raybould’s favor. (She won 43.9% as the Liberal candidate in 2015.) The Green voters, on the other hand, did not seem to warm to their near-candidate; the party’s actual candidate did better in this district in 2019 than in 2015 (when the party got 3.1%).

One of my favorite cases is Sherbrooke, in Quebec. The winner was Liberal Elisabeth Briere with 29.3%, edging out an NDP incumbent who won 28.3% in this election. He had won the seat with 37.3% in 2015. Close behind in this year’s contest was the BQ candidate who had 25.8%. Following behind them was a Conservative (10.7%), and Green (4.5%). N’V=4.06!! The Liberals won this by basically standing still in vote share, having lost this district by a wide margin in 2015 when their candidate had 29.8%.

A few interesting tidbits from candidate backgrounds. Bernier’s defeat in his own riding of Beauce was at the hands of a dairy farmer, Richard Lehoux. The Conservatives recruited him because of Bernier’s opposition to supply management policies in the dairy sector. (Info found in the CBC’s Live Blog.) Lehoux won only 38.6% of the vote, but it was sufficient to beat Bernier rather badly, as the latter (elected as a Conservative in 2015 and previously) had just 28.4%.

There were several mayors recruited to run, including a case in Quebec where the Conservatives hoped the candidate’s local popularity would overcome the party leader’s unpopularity. (The specific case was Trois-Rivières; the Conservative finished a close third in a riding the BQ candidate won with 28.5%.) There was also an Olympic medal-winning kayaker, Adam van Koeverden, whom the Liberals recruited in Milton (in Toronto, Ontario) to run against the Conservative Deputy Leader, Lisa Raitt. He defeated her–easily, winning 51.4% to her 36.5%. Presumably his celebrity (and perhaps his local roots, which he made a point to emphasize in an interview after his victory was confirmed) helped him win despite a nationwide swing against the Liberals and in favor of the Conservatives. (She had won 54.4% in 2015.) In other words, while I may emphasize that district politics under FPTP in a parliamentary system is mostly national politics, there is still plenty of room for local and personal factors to matter.

 

What it means for the near term

As to the shape of the government to result, it should be a reasonably stable minority government, although it may not last full term. It can form legislative majorities with either the BQ or the NDP, and thus need not be tied to either one in a coalition. And the NDP certainly is not strong enough to demand a coalition (even if it wanted to try). Nor is it likely strong enough to demand action on electoral reform, even if an election in which two thirds of the voters voted against the governing party, and various other aspects of the outcome can be seen as anomalous, suggests that reform is needed more than ever.

Canada 2019

It is the final Friday before Shemini Atzeret, also known as Election Day in Canada this year, And what an interesting campaign it has been! The polls have moved quite a lot, especially recently. The New Democrats (NDP) seem to be enjoying a surge. Not on anything like the scale of 2011, but still something notable, as it was not long ago that there was talk about the Greens possibly passing them for third place. The Greens have slipped somewhat, as has been the case in past campaigns. No longer do they look likely to win as many as four seats; two (which is their current number) looks most likely.

The striking thing is that the poll aggregate at CBC (compiled by Éric Grenier) shows both major parties–incumbent seat-majority Liberal and opposition Conservative) barely above 30% of the vote (31.7-30.8 at my latest check). From 1949 to present, the largest party has never had a vote percentage below 36.3% (in 2006). So if there is not a late surge of strategic voting, this will be quite a record-breaker.

Projecting seats under FPTP is always a challenge. The CBC Poll Tracker currently has the Liberals significantly favored, despite being marginally behind in votes, 133 seats to 123 (but with wide confidence bands on both).  That would be 39.3% of the seats for the largest party, which would also break the record (from 1949 on) set in 2006 (40.3%, or 124 in what was then a smaller parliament).

Despite being both a plurality reversal and a record low vote percentage (and an extremely close vote margin), the advantage ratio (%seats/%votes) of 1.278 for the largest seat-winner would be just about average. Over 22 elections, the mean advantage ratio has been 1.2897. (Note: I am calculating this as the share of the largest seat-winner over its vote share, not over the share of the largest vote-winner, when those diverge.) For those who know Canadian electoral history, I will note that advantage ratios of around 1.2-1.3 have occurred in 1965, 1968, and 2008 (among others). Thus even if the specific vote totals may be very unusual, the workings of FPTP, given the actual votes, is fairly “typical” for Canada.

As for the other parties, I mentioned the NDP surge. But just as noteworthy is the surge of the Bloc Quebecois, which may turn out (again) to be the single most important factor in preventing a majority of seats. The BQ is currently polling just under 7% nationwide, while the Greens are just over 8%.

Of course, the BQ and Green fortunes will diverge in seats. It is very helpful for votes-seats conversion to be a regional party under FPTP, and not useful to be relatively more dispersed. So the BQ is currently estimated to get 38 seats, about the same as a much larger national party, the NDP (41) and vastly more than the also larger–in votes–Greens (2).

Regarding those surges I mentioned. The BQ was, according to the polling aggregate on only about 20% in Quebec as recently as one month ago. Now it is up to almost 30%, and just behind the Liberals’ percentage in the province (31%, having been 37% a month ago). The Conservatives have really crashed in Quebec, down from 22% a month ago to just under 16% now. The latter puts them not too far ahead of the NDP, who are now on about 14% in the province.

Nationally, the NDP was at only about 13% a month ago, but is approaching 19%. A rising vote share tends to lift the seat share–even for a national third party under FPTP. While a month ago, the Poll Tracker had the party at only 15 seats, its 41 projected now represents an increase by a factor of 2.7 when its votes have increased only 1.27 (19/15). The party would still be significantly under-represented by the electoral system, but it has reached a point where it gains a lot of seats by a small increase in votes (assuming it holds and that Grenier’s swing assumptions are reasonable, etc.).

The NDP has also pulled narrowly ahead of the Liberals in the polling aggregate in British Columbia, although still well behind the leading Conservatives.

As for the Greens, their slide has been quite abrupt. They were over 10% as recently as the first of October and were projected to win 4 seats as recently as 16 Oct.

The sixth party in the picture, the far-right Peoples Party of Canada, looks likely to win only the seat of its leader, Maxime Bernier. The riding (district) is Beauce, in Quebec, in which Bernier has held as a Conservative since 2006 until defecting from that party in 2018. (I see the Rhinoceros Party has found a candidate with the same name to put up against him.) For months, the PPC has been at either zero or one seat in the projection.

As for who will form a government, the Liberals seem best placed, even if the result is as short of majority as the Poll Tracker projects. It is possible that they will be weak enough to have to form a coalition with the NDP, even though probably the Liberals would prefer a minority government. On current numbers, Liberal+NDP would be a very bare majority. The coalition or a minority government might need working arrangements of some sort with the Greens and/or BQ as well.

It is much harder to see how the Conservatives can form government, even if they end up edging out the Liberals for a seat plurality. Conservative leader Scheer has already begun the spin just in case, claiming this week (incorrectly) that the party with the most seats gets the first shot at forming a government.

NDP leader Jagmeet Singh has said he would try to form a coalition with the Liberal Party if the Conservatives have the most seats. And PM Justin Trudeau would have the legal right to attempt to work out such a deal and meet parliament to try to retain office. Presumably, Singh (and the Green leader, Elizabeth May) would attempt to extract a concession that 2019 be the last election under FPTP.

Quebec to have electoral reform referendum

Per CTV News Montreal, the CAQ governing party in Quebec promises a referendum on a specific electoral-reform proposal to be held concurrent with the next general election in 2022.

The CAQ government on Wednesday introduced its electoral reform law, but backed away from its 2018 campaign promise to have it in place in time for the next general election.

The system is a form of mixed-member proportional representation (MMP), but a complex one. And not very proportional.

The number of seats in the National Assembly would remain 125. The new electoral law would divide Quebec into 80 larger electoral divisions that will mainly be the same as federal ridings, and 17 wider regions:

  • 80 MNAs would be elected according to the current system

  • 45 MNAs on a list of candidates would be divided among the parties, according to the percentage of votes obtained in the 17 regions

Thirty six percent of seats for the list tier is certainly on the small side, and the proportionality would be reduced further by that list tier itself being districted. Note that the mean number of seats per compensation region is only 2.65.

Based on further detail that I learned from Manuel on Twitter (and that I trust he will not mind my sharing here), we can see yet more ways that this proposal is designed to limit proportionality.

…it’s a very constrained implementation of PR, limited by a provincial-level 10% (yes, ten percent) threshold; and districted MMP in seventeen regions, with a new variation of the D’Hondt rule that skews seat distributions in favor of the larger parties.

Regarding the seat allocation method for the compensation seats (which will limit how compensatory it actually will be):

In Scotland and Wales the modified D’Hondt divisors are N+1,N+2,N+3, and so on, where N = number of single-member seats. In the Quebec proposal, they are N/2 + 1, N/2 + 2, N/2 + 3, N/2 being *half* the number of single-member seats, rounded up, and resulting in lower divisors.

One additional detail: the bill provides for separate allocations of single-member and PR list seats among regions – according to the number of registered voters – which guarantee all but one region a minimum of two seats. This would cost Montreal – a PLQ bastion – three seats.

I would still consider this MMP*, as there is a compensation mechanism. I am on record as considering even the Jenkins Commission proposal in the UK to be MMP, albeit with lots of caveats given it was also designed to be about as weak on the P as could be.

Regarding the election of 2018 when the CAQ came into power–surprisingly, with an absolute majority of seats–and the electoral-reform promises made at the time, see this earlier planting.


  • * UPDATE: I am now not sure about this; I need more time to think it through, and that will have to wait till some time in 5780! In the meantime, see this Twitter thread. I think the issue hinges on whether the “modification” to D’Hondt is actually more like Imperiali. While Taagepera and I list Imperiali divisors in our book as being part of the family of PR allocation formulas, we both now believe that it should not be. We were prompted to this view by an email exchange earlier in 2019 with Steven Verbanck (regular F&V commenter). Anyway, to be continued…

Newfoundland and Labrador 2019

Now, this is a close election! Newfoundland and Labrador held its provincial election on 16 May. The result was the Liberal Party winning exactly half the seats–apparently. One of their losses is by five votes. Not five percentage points. Five votes. The apparent winner is the NDP candidate. There is likely to be a recount.

If the result holds, the NDP has won three seats in the 40-seat assembly, up from two in the previous election. The Liberals had 31 seats last time, so this is some electoral rebuke, even if it ends up back with a majority. The Progressive Conservative Party, which won 15 seats, has not conceded defeat, and the leader has said he will be calling on the NDP and two independents (who are ex-Liberals) to consider a possible bid for power if the Liberals do not win their 21st seat.

The Liberal vote total percentage was 43.9, PCs 42.6, NDP 6.3.

PEI 2019: Provincial assembly election and MMP referendum

Prince Edward Island election day was today. Results appear to be pointing towards a lead in votes and seats for the Progressive Conservatives. Thus the expectation (at least according to some polling) that the Greens might form the government looks unlikely now. The Green Party appears to be in second place, although closer (in votes) to the third place Liberals than to first place. The Liberals are the outgoing governing party, with a seat majority.

It looks like it will be a minority situation, which I think will be a first for PEI.

Voters were also voting in a referendum on whether to replace FPTP with a mixed-member proportional (MMP) system, with the voter brochure showing it as an open-list variant. That looks like a close call at this point, but most likely it has been defeated. To pass, the MMP proposal requires not only a majority of votes, but also a win in 17 of the 27 districts. At the moment, CBC is reporting it will win no more than 15 (and may not have a provincewide majority anyway).

PEI has been here before, having voted in a non-binding ballot (conducted by phone or online) for MMP in 2016, and having defeated an earlier MMP referendum by a big majority in 2005.

Today’s referendum had an odd ballot format: the NO option appears above the YES option. I am not sure I have ever seen that before.

(There is one district that did not vote today in the assembly election; a candidate, of the Greens, died in a canoe accident last Friday, so there will be a by-election at a future date.)

BC: Sticking with FPTP

I thought it would at least be close. It was not.

61.3% of voters in British Columbia voted to keep the FPTP system.

In the (now moot) second ballot question, MMP was favored over the other options, on 41.2%, with DMP a (surprising?) second on 29.5% and RUP on 29.3%. A total of 831,760 votes were cast in the second question, versus 1,380,753 in the main question. So fully 40% of voters did not answer the “what if” question.

The second question permitted a ranking of choices on the three alternatives. In the redistribution of preferences, MMP won with 63.05% (of 779,698 votes).

In 2009, I wrote a post entitled “BC: FPTP forever?” And then the question of change came up again a mere nine years later. But this is a pretty decisive defeat. I know forever is a long time. But it seems unlikely for proportional representation to get another chance anytime soon.

Is AV just FPTP on steroids?

In debates over electoral systems in Canada, one often hears, from otherwise pro-reform people, that a shift to the alternative vote would be worse than the status quo. It is easy to understand why this view might be held. The alternative vote (AV), also known as instant runoff (IRV), keeps the single-seat districts of a system like Canada’s current first-past-the-post (FPTP) system, but replaces the plurality election rule in each district with a ranked-ballot and a counting procedure aimed at producing a majority winner. (Plurality winners are still possible if, unlike in Australia, ranking all candidates is not mandatory. The point is that pluralities of first or sole-preference votes are not sufficient.)

Of course, the claim that AV would be FPTP on steroids implies that, were Canada to switch to AV, the current tendency towards inflated majorities for a party favored by less than half the voters would be even more intensified. This is plausible, inasmuch as AV should favor a center-positioned party. A noteworthy feature of the Canadian party system is the dominance, most of the time, by a centrist party. This is unusual in comparison with most other FPTP systems, notably the UK (I highly recommend Richard Johnston’s fascinating book on the topic). The party in question, the Liberal Party, would pick up many second preferences, mainly from the leftist New Democratic Party (NDP) and so, according to the “steroids” thesis, it would thus win many more seats than it does now. It might even become a “permanent majority”, able to win a parliamentary majority even if it is second in (first-preference) votes to the Conservatives (who thus win the majority or at least plurality of seats under FPTP). The “steroids” claim further implies that the NDP would win many fewer seats, and thus Canada would end up with more of a two-party system rather than the multiparty system it has under FPTP.

There is a strong plausibility to this claim. We can look to the UK, where AV was considered in a referendum. Simulations at the time showed that the Liberal Democrats would stand to benefit rather nicely from a change to AV. While the LibDems are a third party, heavily punished by the FPTP electoral system even when they have had 20% or so of the votes, what they have in common with the Canadian Liberals is their centrist placement. Thus, perhaps we have an iron law of AV: the centrist party gains in seats, whether or not it is already one of the two largest parties. An important caveat applies here: with the LibDems having fallen in support since their coalition with the Conservatives (2010-15), the assumptions they would gain from AV probably no longer apply.

On the other hand, we have the case of the Australian House of Representatives, which is elected by AV. There, a two-party system is even stronger in national politics than in the FPTP case of the UK, and far more so than in Canada. (When I say “two party” I am counting the Coalition as a party because it mostly operates as such in parliament and its distinct component parties seldom compete against one another in districts.)

It is not as if Australia has never had a center-positioned party. The Australian Democrats, for example, reached as high as 11.3% of the first-preference votes in 1990, but managed exactly zero seats (in what was then a 148-seat chamber). Thus being centrist is insufficient to gain from AV.

Nonetheless, the combination of centrism and largeness does imply that Canada’s Liberals would be richly rewarded by a change to AV. Or at least it seems that Justin Trudeau thought so. His campaign promised 2015 would be the last election under FPTP. While he did not say what would replace it, he’s previously said he likes a “ranked ballot” and he pulled the plug on an electoral-reform process when it was veering dangerously towards proportional representation.

Still, there are reasons to be somewhat skeptical, at least of the generalization of the Australian two-party experience. The reasons for my caution against the “steroids” view are two-fold: (1) the overlooked role of assembly size; (2) the ability of parties and voters to adapt.

Assembly size is the most important predictor of the size of the largest party, disproportionality, and the effective number of seat-winning parties in countries that use single-seat districts. (It is likely relatively less important when there are two rounds of voting, as in France, but still likely the most important factor.) This is a key conclusion of Votes from Seats. It is thus important not to overlook the fact that Australia has an assembly size considerably smaller than Canada’s. In the book, Taagepera and I show that Australia’s effective number of seat-winning parties and size of largest parliamentary party are almost what we would expect from its assembly size, even if FPTP were used. (See also this earlier post and its comment thread; how close it is to expectation depends on how we count what a “party” is.) The data are calculated over the 1949-2011 period, and the effective number of parties has been just 1.10 times the expectation from the Seat Product Model (which is based only on assembly size when single-seat districts are used). Similarly, the average largest party has been 93% of the expected size (averaging 50.5%  of seats when we would expect 54.2%).

Thus we do not need to invoke the alleged steroids aspect of AV to understand the dominance of two parties in Australia. But this does not mean it would not make a difference in Canada. Consider that the current effective number of parties and size of the largest party in that country, averaged over a similar period, are also just about what we should expect. The multipartism, including periodic minority governments, that characterize Canada are not surprising, when you use the Seat Product Model (SPM). They are surprising only if you think district magnitude is all that matters, and that FPTP is FPTP. But it isn’t! An electoral system using the FPTP electoral rule with an assembly of more than 300 seats is a different, and more multiparty-favoring, electoral system than one with 150 seats. Replace “FPTP” in that sentence with “AV” and it is surely still true.

But what about the centrist party, the Canadian Liberals? Surely AV would work differently in this context, and the Liberals would be a much more advantaged party. Right? Maybe. If so, then it would mean that the SPM would be overridden, at least partially, in Canada, and the largest party would be bigger than expected, for the assembly size, while the effective number of parties would be lower than expected. Of course, that’s possible! The SPM is devised for “simple” systems. AV is not simple, as we define that term. Maybe the SPM is just “lucky” that the one country to have used AV for a long time has the expected party system; or it is lucky that country has the “correct” assembly size to sustain two-party dominance. (Australia is the Lucky Country, after all, so if the SPM is going to get lucky somewhere, it might as well be Australia.)

This is where that other factor comes in. While no one has a crystal ball, I am going to go with the next best thing. I am going to say that the SPM is reliable enough that we can predict that, were Canada to have AV, it would have an effective number of parties around 2.6 and a largest party with around 48% of seats. In other words, just about where it has been for quite some time (adjusting for the House size having been a bit smaller in the past than it is now). Note these are averages, over many elections. Any one election might deviate–in either direction. I won’t claim that a first election using AV would not be really good for the Liberals! I am doubting that would be a new equilibrium. (Similarly, back in 2016 I said my inclination would not be to predict the effective number of parties to go down under AV.)

Parties and voters have a way of adapting to rules. Yes the Liberals are centrist, and yes the Conservatives are mostly alone on the right of the spectrum (albeit not quite as much now, heading into 2019, as in recent years). But that need not be an immutable fact of Canadian politics. Under AV, the Liberals might move leftward to attract NDP second preferences, the NDP center-ward to attract Liberal and even Conservative second preferences, the Conservatives also towards the center. It would be a different game! The Greens and other parties might be more viable in some districts than is currently the case, but also potentially less viable in others where they might win a plurality, but struggle to get lower ranked preferences. The point is, it could be fluid, and there is no reason to believe scenarios that have the largest party increasing in size (and being almost always the Liberals), and correspondingly the effective number of parties falling. With 338 or so districts, likely there would remain room for several parties, and periodic minority governments (and alternations between leading parties), just as the SPM predicts for a country with that assembly size and single-seat districts.

As I have noted before, it is the UK that is the surprising case. Its largest party tends to be far too large for that huge assembly (currently 650 seats), and its effective number of seat-winning parties is “too low”. Maybe it needs AV to realize its full potential, given that the simulations there showed the third party benefitting (at least when it was larger than it’s been in the two most recent elections).

Bottom line: I do not buy the “FPTP on steroids” characterization of AV. I can understand were it comes from, given the presence in Canada of a large centrist party. I just do not believe Liberal dominance would become entrenched. The large assembly and the diversity of the country’s politics (including its federal structure) both work against that.

I agree with electoral reformers that PR would be better for Canada than AV. I also happen to think it would be better for the Liberals! But would AV be worse than FPTP? Likely, it would not be as different as the “steroids” claim implies.