UK 2017: Green Party won’t stand in Ealing constituency

Here is something we do not see in First-Past-the-Post elections* as much as the Duvergerianists seem to think we should: one party agreeing not to have a candidate in order to avoid vote-splitting in a district.

The Green Party has pulled out of a crucial election seat in a bid to help the Labour Party beat the Tories – the first tactical withdrawal of its kind ahead of the general election.

The decision is expected to allow more votes to go to Labour MP Rupa Huq, who beat the Conservatives with a majority of just 274 votes in 2015, when no other party managed to attract more than seven per cent of the vote.

Green Party members in Ealing — where the party won 1,841 votes in the 2015 election — voted not to field a candidate last week, after Ms Huq promised to campaign for voting reform and the environment.

* Except in India!

BC 2017: Non-Duvergerian watch

British Columbia votes for its provincial assembly on 9 May. Eric Grenier’s vote and seat projections at CBC suggest it could be a “non-Duvergerian” outcome, especially in the votes. The NDP looks likely to win a majority of seats, manufactured by the electoral system, as its votes are likeliest to stay below 45%. The Liberals are running well behind, but are also likely to be over-represented due to their more efficient votes distribution: Grenier’s average projection for the party would put them on just under 35% of votes but 39% of seats.

The non-Duvergerian aspect of the election is the Greens: average projection of 20% of the votes, which is on the high side for a third party under FPTP. The mechanical effect will crush them, however: average seats only 2 of 87. That, of course, is “typical” FPTP.

Where things get interesting is if the Greens rise even just a few percentage points. The “high” projection takes their votes up only to around 23% but their seats to 12 or more (around 14%)! Clearly, they are running second in many districts–particularly on Vancouver Island.

The reason this pattern is non-Duvergerian is that the so-called Duverger’s law says voters tend not to want to waste their votes on a third party. They should “coordinate” with the more-preferred of the two big parties. Further, this defection should be more likely after the third party has suffered from the mechanical effect of FPTP in past elections, as the Greens in BC have. Instead, their support is evidently growing.

But there is not much incentive to choose between the major parties when you have three-party competition throughout much of the province, and the third party could win a significant number of seats even if it stays well below 50% in the districts where it is most viable.

The BC NDP platform promises: “We’ll hold a referendum – and campaign for the “yes” side – on replacing our outdated voting system with a proportional one.”

Will they follow through if FPTP delivers them a majority?

Update: The tracker of where the party leaders are campaigning is interesting. Of course, there is much emphasis on swing districts, particularly for the NDP. However, this quotation from Richard Johnston (UBC political scientist) is spot on:
“You do have to campaign everywhere; you have to validate the existence of your candidates.” In Chapter 10 of Votes from Seats (forthcoming, Cambridge University Press), Rein Taagepera and I refer to this phenomenon as the “embeddedness” of districts in nationwide (here, provincewide) politics. We do not consider non-Duvergerian districts to be quite the puzzle that others do, because we expect voters to be more oriented towards the aggregate outcome than towards their own district, and parties to care about “showing the flag” even in districts they may not be very likely to win.

Magnitude and party advantage ratios

What is the relationship between district magnitude and a party’s advantage in seats, relative to votes?

Using the same district-level dataset that Rein Taagepera and I use for our forthcoming Votes from Seats (and which has its original source in CLEA), we can answer this question. The sample I am using here is simple PR systems–those in which the districts are the sole locus of seat allocation (i.e., leaving out two-tier systems).

The advantage ratio (A) is the best way to examine this; it is just a party’s percentage of seats, divided by its percentage of votes.The table below shows the average A for magnitudes (M) ranging from 2 to 7. The larger the A, the more a given party is over-represented. The table shows mean A values for the first, second, and third largest parties (by vote share in the district), as well as how many districts of a given magnitude are in the dataset .

M A, 1st A, 2nd A, 3rd Num. obs.
2 1.29 1.50 0.00 172
3 1.34 1.10 0.50 98
4 1.25 1.15 0.50 103
5 1.26 1.14 0.64 112
6 1.19 1.17 0.73 72
7 1.19 1.09 0.81 79

We can see that M=2 is the only case where the second largest party gains more than the largest does, on average. This result is well known from the experience in Chile. I had thought we might see a similar pattern at M=4. However, we do not. As with all other magnitudes except 2, the largest party at M=4 tends to have a bigger advantage ratio than the second, although the two largest parties’ A values are closer here than in odd M‘s just above and below.

Also of interest fro the same query to the dataset, we find that the lowest magnitude at which A<1.10 for the largest party is M=17. The average for the largest party never falls below 1.00. The second party first falls to A<1.10 at M=13 and then stays right around 1.00 through all higher values.

As for the third largest party, it stays, on average below A=1.00 till M=13, but falls below 1.00 again at several higher M values. The fourth largest party has to wait till M=20 (and likewise has some higher magnitudes where it falls below 1.00).

At higher magnitudes, these average values tend to bounce around a bit, mainly because the sample at any given magnitude is small and thus subject to vagaries of country-level (or district-level) factors (including allocation rules, although the vast majority of these are D’Hondt).

I have long “known” that 4-seat districts tended to under-represent the largest party, relative to the second largest. Well, apparently one should check what one “knows”. Thanks to Jack (on Twitter) for the prompt to investigate.

Netherlands, compared to the Seat Product expectation

The recent election in the Netherlands was noteworthy for its high fragmentation. But was it higher than we should expect, given an extremely proportional electoral system? If so, how much higher?

Fortunately, from Taagepera’s Seat Product Model, we have a baseline against which to compare any given election. For “simple” electoral systems–those with a single tier of allocation and a basic PR formula (or FPTP)–we expect:


NS is the effective number of seat-winning parties, whereas s1 is the seat share of the largest party. MS is the seat product, defined as the mean district magnitude, times the assembly size. The derivation of these models for expectations may be found in Taagepera (2007), and is also summarized in Li and Shugart (2016) and my forthcoming book with Taagepera, Votes from Seats.

Two important points about these models: (1) They are not mere regression estimates, bur rather are derived deductively; (2) On average, they are remarkably accurate. For long-term European democracies, the mean ratio of actual NS to the model expectation is 1.007; for s1 it is 1.074. (They are not substantially less accurate for other regions or younger democracies, but given the topic of this post, the longer-run European democracies are the most relevant comparison set. The ratios reported are based on 219 individual elections.)

For the Netherlands, with a single nationwide district, MS=150*150=22,500. This means we should expect, on average, in an electoral system like that of the Netherlands, that NS=5.31 and the largest party has 28.6% of the seats (s1=0.286). In other words, we should expect the Dutch party system to be quite fragmented.

In the graphs below, we compare the actual values in each election since 1945 to the Seat Product expectation.

First, for NS.

Now, for s1.

Strikingly, both values are well off the expectation now and have been in some other recent elections–but not so much as recently as 2012 or 2006. The 2017 election appears to be a continuation or acceleration a trend, but that trend has been somewhat irregular. Note, however, a bit farther back in the past there were elections in which NS was much lower than expected, and s1 much higher–in other words, when fragmentation was less than expected. (Note to readers: On 31 March I revised this paragraph to better reflect the recent trends shown in the graph.)

Over the entire period, the mean effective number of seat-winning parties has been 5.08, and the mean largest seat share has been 0.29. In other words, the Netherlands has not been exceptional in its long-term averages, given its extremely high seat product.

A key question is whether fragmentation will again come back closer to expectation. This is not a question the Seat Product Model can answer. But note that if we had been running this test in about 1986, I might have said, “will the Dutch electoral system ever again fragment, like we’d expect?” Sometimes things even out, sometimes they don’t.

Obviously, the fragmentation inn 2017 is far higher, relative to the baseline than it was during the previous (and brief) fragmenting around 1970. Perhaps that means the Dutch party system has entered a new phase from which there is no turning back. The very high proportionality of the system means it can sustain this level of fragmentation without anyone being seriously under-represented. On the other hand, one might want to be careful about assuming recent trends can’t reverse themselves. Parties could merge, or voters could tire of voting for small parties that are only bit players in policy-making.

The value of the Seat Product Model is it lets us go beyond simply saying “the Netherlands uses PR, so fragmentation is no surprise” or, alternatively, “fragmentation is out of control in the Netherlands”. It lets us say just how much the fragmentation in the Netherlands is out of whack with expectation. In 2017, the precise answer is that NS is 1.62 times the expectation, while s1 is 77% of expectation. That degree of divergence from the expectation is almost at the 99th percentile for NS among European countries; the divergence for s1 is at about the 18th percentile.

Will actual and expected values again converge in the Netherlands? Stick around for a few more elections and see.

Should New Zealand do away with by-elections?

In New Zealand’s MMP system, there are by-elections if there is a vacancy between general elections in a single-seat district. This is not a mandatory feature of MMP systems; Germany, for example, has no by-elections. A vacancy in a district is filled off the list of the party of the vacating member.

Nigel Roberts, a leading New Zealand expert on elections and electoral systems, writes in the Dominion Post that New Zealand should end the practice of by-elections. In making the case, he refers to a by-election in the constituency of Mt Albert, which is a safe Labour seat. The Labour Party’s candidate in the by-election, Jacinda Ardern, already is an MP, via the party list. Thus the effect of her winning (which she did) is simply to shift the type of mandate she has*, and have her replaced as a list MP by the next available candidate on the Labour list from the preceding election.

Roberts suggests adding a regional component to the lists in order to ensure that the replacement is from the same region as the district in which the vacancy has occurred.

A potential problem with the proposal is the fact that sometimes a by-election really does shift who controls a district and sometimes can even change the nationwide balance between parties (as happened in a recent case in Northland district). Roberts takes the position that this is better avoided, so as not to change potentially the majority for the government. “Party votes cast in general elections should make or break governments – not electorate votes cast in by-elections,” he says.

I am curious to know what readers think of the proposal.

* As well as, sadly, deprive us of my favorite case of a list MP “shadowing” the district-elected MP.

Uttar Pradesh, 2017

Election results have been released for the state assembly of Uttar Pradesh, India’s largest state. It was a big win for the federal ruling party, the BJP. The seat tally shows 312 for the BJP, with the second highest being the Samajwadi Party (SP) at 47. The SP, the ruling party since 2012, was in a pre-election coalition with the Indian National Congress (INC), which won just 7 seats. The Bahujan Samaj Party (BSP), which has been a significant party in the state in the past, won 19 seats.

Unlike 2012, when the SP majority in the assembly was achieved on not even 30% of the vote, this year’s BJP victory was a big win in votes, too. Not a majority, but a decisive plurality, at 39.7% of the vote. The SP-INC combine had 28.0% and the BSP 22.2%.

Note that the BJP managed a three-fourths majority (77.4%) of the 403 seats on not even 40% of the vote. The advantage ratio (%seats/%votes) was 1.95. That must be one of the biggest manufactured majorities under FPTP anywhere, at least in a large assembly.

Several other states have had recent elections as well. The news was better for the struggling INC in some, including Punjab, Goa, and Manipur, though its pluralities in these are short of majority status. The Aam Aadmi Party (which governs Delhi, but has had minimal success elsewhere) managed a distant second place in Punjab. See the results at the second link in this entry.

New Brunswick electoral reform proposal (yes, again)

The New Brunswick Commission on Electoral Reform has issued its report, “A pathway to an inclusive democracy”.

There are many recommendations regarding changes to voting procedures in the proposal, but those that focus directly on the electoral system are as follows (quoting form p. 19):

The government enhance the voting system by moving to Preferential Ballots.
Š Consideration be given to some form of Proportional Representation during the process of considering the redistribution of electoral boundaries.

While preferential ballots could mean STV, from the overall context of the report, it is clear that “Preferential Ballots” is a term limited in application to the alternative vote (instant runoff), in other words keeping single-seat ridings (districts). The weak “consideration” for “some form of” PR follows an indication earlier in the report that exploration of proportionality was “not within the mandate of the commission”, but that the commission would be “remiss” not to address the issue.

New Brunswick once had an electoral commission report in favor of a mixed-member proportional system. The recommendation was never put to a vote–notwithstanding that the decision to shelve the proposal came after yet another anomalous outcome in a provincial election. And that anomaly was not the last, so far, even if the latest election was somewhat “normal” (by FPTP standards).

Given its record, New Brunswick has an “objective” need for electoral reform if any democratic jurisdiction does. I doubt the alternative vote really is the answer to its electoral needs. And, given the recent past in the province and elsewhere in Canada, including at the federal level, it might be getting ahead of the story to expect even such a tepid reform to happen. But there the issue is, again, in a nice independent report.