The data have been updated. They now represent 100% of votes counted on election night.

Wow. What a result. The broad national narrative of Election 2020 for each party seems clear:

However there is also much to be said about the individual constituencies at play. That is what I’m going to do in this post. I’m not making an argument in this post, just exploring the data to see what happens.

A couple of notes first:

  1. These data were scraped from the Electoral Commissions website at around 1am NZT, when just under 100% of advance and ordinary votes had been counted. They may have changed marginally since then. N.B. This is no longer true. See the note above.
  2. Special votes won’t be counted for some time, which, given how tight some of the constituency results were, might effect this analysis.
  3. This analysis was conducted late at night – taking advantage of my time difference from being based in Singapore – and quickly so it might not be right. I have released my source code on Github, please let me know if something looks off.
  4. Please feel free to email me at mp (at) mitchellpalmer.nz if you have any questions.

Why is this interesting?

Finding out where the votes for each party were found tells us a lot about their electoral strategy and the coalitions they have built. It also lets us find out who the most popular MPs are, aside from their party affiliation.

This election, however, it is particularly interesting for two reasons.

Firstly, because of the utter implosion of the National party vote but the smaller fall in their electorate votes, a significant proportion of National’s seats will be filled by electorate MPs. Thus, while your electorate vote may not decide the government, it will shape the balance of power within the opposition.

Secondly, three minor parties may have managed to sieze or hold electorates: ACT retained its traditional stronghold of Epsom with an increased majority; the Maori Party have most likely siezed Waiariki; and, after a much-reported-on three-way race, the Greens look to have taken Auckland Central. Given the coat-tailing rules in MMP, a growing trend of minor parties winning electorates could substantially change the make-up of Parliament.

How did the parties do?

Clearly, National significantly outperformed in candidate votes compared to their party vote performance. That is mirrored in the constituency counts: National had the plurality (i.e., the most votes) of candidate votes in 26 electorates, but the plurality of party votes in only 4. Why? Three possibilities occur to me (ranked in order of estimated importance):

  1. Electorate votes are sticky: Perhaps voters are less willing to abandon their local MP, to whom they can attach a face and a name, than parties, which after all are simply brands. Given National won the most electorates in 2017, that this stickiness favoured National is unsurprising.
  2. National’s local campaigns were better than their national campaign: Perhaps the collegial nature of constituency committees and the independent mandates of MPs with their supporters meant that local campaigns worked together better than the chaotic national National Party.
  3. National’s candidates were better than Labour’s candidates: In my view, this is definitely true in many parts of the country (e.g., Hutt South), but I struggle to think of any non-partisan reason this would be true generally. If it is true though, it certainly would help explain this phenomenon.

As an aside, readers may be surprised to see such strong candidate vote performances from ACT and Greens, both of which have been known to run party vote-focused campaigns. This can mostly be explained by strong performances in their targetted ‘backstop’ seats (Epsom and Auckland Central), which they presumably seek/sought as an insurance policy to keep them in Parliament if they recieved less than 5% of the party vote. Indeed, 20.22% of ACT’s total electorate votes were in Epsom and 7.46% of the Greens’ total electorate votes were in Auckland Central. By contrast, if Green candidate votes were equally distributed across the country, given they ran in 60 seats, one would expect them to have recieved 1.67% of their candidate votes in each seat.

As mentioned above, the National Party achieved a plurality in only four of the 72 electorates this election. Which were those seats?

electorate party party_vote_share
Epsom National Party 39.87
Tāmaki National Party 38.40
Taranaki-King Country National Party 37.49
Waikato National Party 38.65

Notably absent from that list are National strongholds like Pakuranga (where Simeon Brown won by 9756), Selwyn (where Nicola Grigg won by a distance of 4943) and Judith Collins’ own seat of Papakura (which she took by 5925 votes). Those are a lot of traditionally National seats where another party (i.e., Labour) won the most votes. Those are seats National may well have lost in a first-past-the-post system.

But, perhaps National suffered from the success of its resurgent partners, ACT? Those are still votes for the right, so they shouldn’t count as real loses, the logic might go. While that certainly does help, it doesn’t make a real difference: In a good-old-fashioned two-party FPP election, National would still have lost resoundingly. When one sums the left bloc (Greens and Labour) and the right bloc (ACT and National), the right still only takes 12 seats out of 72 avaliable, none of which they would hold by more than 3000 votes. Even Selwyn, long National’s safest seat or close to it, would have been marginal: The right led there by less than 700 votes.

electorate right_bloc left_bloc right_majority
Taranaki-King Country 16849 13971 2878
Waikato 17249 14548 2701
Tāmaki 17460 15153 2307
Epsom 16618 14313 2305
Whangaparāoa 18710 16508 2202
Southland 17148 15055 2093
Port Waikato 16512 14510 2002
Papakura 15354 13996 1358
Pakuranga 15404 14056 1348
East Coast Bays 15500 14515 985
Selwyn 17625 16996 629
Kaipara ki Mahurangi 16858 16273 585

How did the candidates do?

There appears to be a strong relationship between how a party performed and how its candidates performed. Plugging the party vote and candidate vote into a simple linear regression shows that, for a major party candidate in a general electorate, 61.17% of the variation in their candidate vote can be predicted from the party vote. Once the model accounts for the overall differences between National and Labour this year, the proportion accounted for shoots up to 79.19%.

The obvious question then is “What about that 20.81%”? Which candidates did well? By regressing the candidate vote against both the party from which the candidate comes and that party’s party vote, we can come up with the predicted result of an ‘average’ National/Labour candidate standing in that seat and work out which candidates beat that ‘benchmark’. Here are the list from Labour:

electorate candidate winner predicted_cv candidate_vote outperformance
Mt Albert ARDERN, Jacinda TRUE 15082 23198 8116
Wellington Central ROBERTSON, Grant TRUE 15461 22015 6554
Wigram WOODS, Megan TRUE 17400 20371 2971
Christchurch Central WEBB, Duncan TRUE 17149 19755 2606
Remutaka HIPKINS, Chris TRUE 22423 24911 2488
Mt Roskill WOOD, Michael Philip TRUE 14940 17356 2416
Taranaki-King Country ROBERTS, Angela FALSE 10421 12649 2228
Palmerston North UTIKERE, Tangi TRUE 17796 19467 1671
Rongotai EAGLE, Paul TRUE 20029 21594 1565
Ilam PALLETT, Sarah TRUE 15006 16381 1375
New Lynn RUSSELL, Deborah TRUE 17882 19212 1330
Takanini LEAVASA, Neru TRUE 12757 13926 1169
Waikato LEONI, Kerrin FALSE 11720 12868 1148
Southland MITCHELL, Jon FALSE 11619 12741 1122
Whanganui LEWIS, Steph TRUE 18403 19459 1056
Panmure-Ōtāhuhu SALESA, Jenny TRUE 15802 16784 982
Manurewa WILLIAMS, Arena TRUE 13672 14534 862
Kelston SEPULONI, Carmel Jean TRUE 16794 17594 800
Ōhāriu O’CONNOR, Greg TRUE 18970 19580 610
West Coast-Tasman O’CONNOR, Damien TRUE 17677 18275 598
Māngere SIO, Aupito William TRUE 14929 15515 586
Hamilton East STRANGE, Jamie TRUE 14742 15254 512
Hamilton West SHARMA, Gaurav TRUE 16461 16950 489
East Coast ALLAN, Kiri TRUE 17938 18367 429
Wairarapa McANULTY, Kieran TRUE 19099 19519 420
Christchurch East WILLIAMS, Poto TRUE 20966 21336 370
Rangitata LUXTON, Jo TRUE 18582 18876 294
Mana EDMONDS, Barbara TRUE 21713 21946 233
Napier NASH, Stuart TRUE 18257 18451 194
Northcote HALBERT, Shanan TRUE 15791 15832 41
Tāmaki BROWN, Shirin FALSE 10693 10668 -25
Tauranga TINETTI, Jan FALSE 14225 14169 -56
Te Atatū TWYFORD, Phil TRUE 17462 17345 -117
North Shore UDANGA, Romy FALSE 12875 12749 -126
Upper Harbour WALTERS, Vanushi TRUE 14348 14142 -206
Banks Peninsula McLELLAN, Tracey Lee TRUE 22312 22038 -274
Kaipara ki Mahurangi LUBECK, Marja FALSE 12676 12397 -279
Tukituki LORCK, Anna TRUE 16744 16427 -317
New Plymouth BENNETT, Glen TRUE 18396 18072 -324
Papakura KANONGATA’A-SUISUIKI, Anahila FALSE 10896 10438 -458
Whangaparāoa FERGUSON, Lorayne Frances FALSE 13585 13061 -524
Selwyn DAVIDSON, Reuben FALSE 14223 13635 -588
Rotorua MAHON, Claire FALSE 13737 13038 -699
Maungakiekie RADHAKRISHNAN, Priyanca FALSE 13197 12433 -764
Invercargill CRAIG, Liz FALSE 16588 15687 -901
Epsom BELICH, Camilla FALSE 8516 7563 -953
East Coast Bays HERNANDEZ, Monina FALSE 10673 9718 -955
Bay of Plenty WARREN-CLARK, Angie FALSE 14457 13457 -1000
Botany CHEN, Naisi FALSE 12902 11890 -1012
Rangitīkei PEKE-MASON, Soraya FALSE 14896 13822 -1074
Auckland Central WHITE, Helen FALSE 9733 8568 -1165
Pakuranga HENRY, Nerissa FALSE 10728 9221 -1507
Northland PRIME, Willow-Jean FALSE 16428 14608 -1820
Dunedin CLARK, David TRUE 22747 20806 -1941
Kaikōura FLIGHT, Matt FALSE 15930 13823 -2107
Waitaki WAIREPO, Liam FALSE 16599 14470 -2129
Whangārei HENDERSON, Emily FALSE 17731 15475 -2256
Coromandel BLOMFIELD, Nathaniel James FALSE 17307 15035 -2272
Ōtaki NGOBI, Terisa TRUE 20347 17953 -2394
Port Waikato KAUR, Baljit FALSE 11770 9321 -2449
Taupō AL-BUSTANJI, Ala’ FALSE 15926 13392 -2534
Taieri LEARY, Ingrid TRUE 24881 22225 -2656
Nelson BOYACK, Rachel TRUE 21319 18625 -2694
Hutt South ANDERSEN, Ginny TRUE 21888 18823 -3065
Waimakariri ROSEWARNE, Dan FALSE 20858 17260 -3598
And from National:
electorate candidate winner predicted_cv candidate_vote outperformance
Hutt South BISHOP, Chris FALSE 11688 16531 4843
Nelson SMITH, Nick FALSE 11163 15048 3885
Waimakariri DOOCEY, Matt TRUE 15609 19236 3627
Maungakiekie LEE, Denise TRUE 10490 13013 2523
Ōtaki COSTLEY, Tim FALSE 14199 16683 2484
Pakuranga BROWN, Simeon TRUE 16748 18977 2229
Invercargill SIMMONDS, Penny TRUE 14468 16372 1904
Northcote BIDOIS, Dan FALSE 12639 14474 1835
Whangārei RETI, Shane TRUE 13861 15639 1778
Taupō UPSTON, Louise TRUE 17037 18646 1609
Rotorua McCLAY, Todd TRUE 12806 14283 1477
Selwyn GRIGG, Nicola TRUE 17208 18578 1370
Rangitīkei McKELVIE, Ian TRUE 14922 16245 1323
Whangaparāoa MITCHELL, Mark TRUE 19425 20710 1285
Waitaki DEAN, Jacqui TRUE 16430 17615 1185
East Coast Bays STANFORD, Erica TRUE 16783 17789 1006
Tāmaki O’CONNOR, Simon TRUE 17573 18560 987
Hamilton East BENNETT, David FALSE 12388 13308 920
Hamilton West MACINDOE, Tim FALSE 11648 12525 877
Southland MOONEY, Joseph TRUE 17032 17817 785
Kaikōura SMITH, Stuart TRUE 15364 16105 741
Coromandel SIMPSON, Scott TRUE 18505 19241 736
Tukituki YULE, Lawrence FALSE 14937 15655 718
New Plymouth YOUNG, Jonathan FALSE 15910 16553 643
Botany LUXON, Christopher TRUE 16105 16661 556
Bay of Plenty MULLER, Todd TRUE 16472 16929 457
Taieri KERNAGHAN, Liam FALSE 11281 11593 312
Waikato VAN DE MOLEN, Tim TRUE 17967 18255 288
Northland KING, Matt TRUE 15066 15337 271
Dunedin WOODHOUSE, Michael FALSE 7254 7485 231
North Shore WATTS, Simon TRUE 16581 16731 150
Māngere LOHENI, Agnes FALSE 2704 2844 140
East Coast TAPSELL, Tania FALSE 13725 13721 -4
Kaipara ki Mahurangi PENK, Chris TRUE 16857 16826 -31
Napier NIMON, Katie FALSE 13968 13926 -42
Auckland Central MELLOW, Emma FALSE 7612 7566 -46
West Coast-Tasman PUGH, Maureen FALSE 13258 13208 -50
Whanganui HIPANGO, Harete FALSE 12782 12638 -144
Papakura COLLINS, Judith TRUE 16508 16363 -145
Tauranga BRIDGES, Simon TRUE 16823 16602 -221
Christchurch Central STEPHENS, Dale FALSE 8781 8332 -449
Wellington Central WILLIS, Nicola FALSE 7550 7080 -470
Mana HAYES, Jo FALSE 9188 8703 -485
Ilam BROWNLEE, Gerry FALSE 14654 14161 -493
Te Atatū NGARO, Alfred FALSE 9704 9121 -583
Panmure-Ōtāhuhu BAKSHI, Kanwaljit Singh FALSE 3829 3243 -586
Christchurch East PLATT, Lincoln FALSE 7611 6881 -730
Taranaki-King Country KURIGER, Barbara TRUE 17071 16281 -790
Palmerston North WOOD, William FALSE 9932 9025 -907
Rangitata HANDS, Megan FALSE 16314 15392 -922
Manurewa SAMARAKONE, Nuwi FALSE 3824 2838 -986
Kelston BEERAM, Bala FALSE 6524 5383 -1141
Rongotai PATTERSON, David FALSE 6732 5558 -1174
Upper Harbour BEZZANT, Jake FALSE 13989 12727 -1262
Wigram CAMPBELL, Hamish FALSE 9299 7987 -1312
Banks Peninsula CHU, Catherine FALSE 12170 10834 -1336
New Lynn WHYTE, Lisa FALSE 10243 8810 -1433
Ōhāriu HUDSON, Brett FALSE 11243 9589 -1654
Wairarapa BUTTERICK, Mike FALSE 15894 14108 -1786
Mt Albert LEE, Melissa FALSE 8428 6621 -1807
Remutaka CROFSKEY, Mark FALSE 9544 7674 -1870
Takanini NAKHLE, Rima FALSE 11357 9378 -1979
Mt Roskill PARMAR, Parmjeet FALSE 10294 7842 -2452
Port Waikato BAYLY, Andrew TRUE 16963 13582 -3381
Epsom GOLDSMITH, Paul FALSE 17347 4840 -12507

Now, we shouldn’t immediately conclude from this that every Labour MP should have campaigned like Duncan Webb and every National MP should have campaigned like Chris Bishop. An MP who did a bad job spreading the party vote message in their constituency, but did a passable one promoting themselves, would do very well on this metric. But we can conclude that a constituency candidate’s fate is not entirely in the hands of their party – they can change it in or against their own favour. (A better model would also account for incumbency bias – outperformers tend to be incumbents, probably because of their preexisting local profile – and perhaps also the depth of the field – so as to avoid unduly punishing candidates like Helen White who run in the three-horse races.)

Where did they do well?

This will be a longer post sometime in the future. In that post, I’ll see what predicts support for each of the parties based on the characteristics of the constituencies. But, in the mean time, here are the party votes cast in the general electorates aggregated into some rough regions (please excuse my poor New Zealand geography, especially residents of the Central North Island – I have no reason to be bad at it. I just am.):

## Joining, by = "electorate"