Last Minute NZ Predictions

It's about 10 minutes since polls closed in NZ, so here are some quick predictions.

As NZ uses First-Past-the-Post, this will be a little different for me. Nevertheless, a good place to start for a quick calculation is the 2017 results. For now, let's just look at the regular electorates, except Botany (held by Advance NZ), Epsom (where ACT has won since 2005), Ilam (where an independent came second last election) and Northland (where NZ First came second). This gives a series of Labour vs National seats we can consider on the raw numbers of votes cast for the two major parties and what proportion were won by Labour:

	Incumbent	Labor	National	Labor (%) 2017
Auckland Central	National	11617	13198	46.81%
Bay of Plenty	National	11356	25352	30.94%
Christchurch Central	Labour	16631	13760	54.72%
Christchurch East	Labour	18439	10959	62.72%
Clutha-Southland	National	7465	21819	25.49%
Coromandel	National	8727	23053	27.46%
Dunedin North	Labour	21259	9505	69.10%
Dunedin South	Labour	21404	12687	62.78%
East Coast	National	12710	17517	42.05%
East Coast Bays	National	6441	22731	22.08%
Hamilton East	National	13165	18975	40.96%
Hamilton West	National	11111	18842	37.09%
Helensville	National	7096	21704	24.64%
Hunua	National	7382	26825	21.58%
Hutt South	National	18113	19643	47.97%
Invercargill	National	12523	18102	40.89%
Kaikōura	National	10401	20594	33.56%
Kelston	Labour	16789	9520	63.81%
Mana	Labour	22709	11729	65.94%
Māngere	Labour	18810	4213	81.70%
Manukau East	Labour	17402	4813	78.33%
Manurewa	Labour	15577	7203	68.38%
Maungakiekie	National	12906	15063	46.14%
Mt Albert	Labour	24416	9152	72.74%
Mt Roskill	Labour	19094	12196	61.02%
Napier	Labour	20677	15457	57.22%
Nelson	National	12452	16735	42.66%
New Lynn	Labour	15840	13015	54.90%
New Plymouth	National	12978	20711	38.52%
North Shore	National	10848	23564	31.52%
Northcote	National	12862	19072	40.28%
Ōhariu	Labour	17084	16033	51.59%
Ōtaki	National	14569	20725	41.28%
Pakuranga	National	7777	22663	25.55%
Palmerston North	Labour	18388	11946	60.62%
Papakura	National	12780	20266	38.67%
Port Hills	Labour	22603	14687	60.61%
Rangitata	National	13663	19994	40.59%
Rangitīkei	National	10519	20809	33.58%
Remutaka	Labour	21725	13116	62.35%
Rodney	National	8579	28140	23.36%
Rongotai	Labour	21146	10246	67.36%
Rotorua	National	10887	18788	36.69%
Selwyn	National	9047	28686	23.98%
Tāmaki	National	8624	24026	26.41%
Taranaki-King Country	National	8595	23854	26.49%
Taupō	National	10276	24611	29.46%
Tauranga	National	10247	21499	32.28%
Te Atatū	Labour	16774	13590	55.24%
Tukituki	National	15467	18280	45.83%
Upper Harbour	National	10301	19857	34.16%
Waikato	National	9108	24560	27.05%
Waimakariri	National	11891	22657	34.42%
Wairarapa	National	13642	16514	45.24%
Waitaki	National	12054	24870	32.65%
Wellington Central	Labour	20873	10910	65.67%
West Coast-Tasman	Labour	18488	12895	58.91%
Whanganui	National	15045	16751	47.32%
Whangarei	National	7767	18734	29.31%
Wigram	Labour	17001	12407	57.81%

Normally I'd compare how this split nationally (36.9:44.4; NAT = 54.61%) compares to the latest polling (45.8:31.1; LAB = 59.56%); calculate a swing of 14.17 percentage points and see how the seats fall if this were uniform across all electorates. However, I've also measured what I'm terming 'shift'; If the Labour vote has moved from 36.9 to 45.8; they've increased by 24.12%; Nationals have similarly reduced by 29.95%. Applying this to the voting turn out of each electorate, we see a very similar patter between the two methods:

	Incumbent	Labor	National	Labor (%) 2017	Swing	Shift			Prediction
Auckland Central	National	11617	13198	46.81%	60.98%	14419	9245	60.93%	Labour
Bay of Plenty	National	11356	25352	30.94%	45.11%	14095	17758	44.25%	National
Christchurch Central	Labour	16631	13760	54.72%	68.89%	20642	9638	68.17%	Labour
Christchurch East	Labour	18439	10959	62.72%	76.89%	22886	7676	74.88%	Labour
Clutha-Southland	National	7465	21819	25.49%	39.66%	9266	15283	37.74%	National
Coromandel	National	8727	23053	27.46%	41.63%	10832	16147	40.15%	National
Dunedin North	Labour	21259	9505	69.10%	83.27%	26387	6658	79.85%	Labour
Dunedin South	Labour	21404	12687	62.78%	76.95%	26566	8887	74.93%	Labour
East Coast	National	12710	17517	42.05%	56.22%	15776	12270	56.25%	Labour
East Coast Bays	National	6441	22731	22.08%	36.25%	7995	15922	33.43%	National
Hamilton East	National	13165	18975	40.96%	55.13%	16340	13291	55.15%	Labour
Hamilton West	National	11111	18842	37.09%	51.26%	13791	13198	51.10%	Labour
Helensville	National	7096	21704	24.64%	38.81%	8808	15203	36.68%	National
Hunua	National	7382	26825	21.58%	35.75%	9162	18790	32.78%	National
Hutt South	National	18113	19643	47.97%	62.14%	22482	13759	62.03%	Labour
Invercargill	National	12523	18102	40.89%	55.06%	15543	12680	55.07%	Labour
Kaikōura	National	10401	20594	33.56%	47.73%	12910	14425	47.23%	National
Kelston	Labour	16789	9520	63.81%	77.98%	20838	6668	75.76%	Labour
Mana	Labour	22709	11729	65.94%	80.11%	28186	8216	77.43%	Labour
Māngere	Labour	18810	4213	81.70%	95.87%	23347	2951	88.78%	Labour
Manukau East	Labour	17402	4813	78.33%	92.50%	21599	3371	86.50%	Labour
Manurewa	Labour	15577	7203	68.38%	82.55%	19334	5045	79.30%	Labour
Maungakiekie	National	12906	15063	46.14%	60.31%	16019	10551	60.29%	Labour
Mt Albert	Labour	24416	9152	72.74%	86.91%	30305	6411	82.54%	Labour
Mt Roskill	Labour	19094	12196	61.02%	75.19%	23699	8543	73.50%	Labour
Napier	Labour	20677	15457	57.22%	71.39%	25664	10827	70.33%	Labour
Nelson	National	12452	16735	42.66%	56.83%	15455	11722	56.87%	Labour
New Lynn	Labour	15840	13015	54.90%	69.07%	19660	9116	68.32%	Labour
New Plymouth	National	12978	20711	38.52%	52.69%	16108	14507	52.61%	Labour
North Shore	National	10848	23564	31.52%	45.69%	13464	16505	44.93%	National
Northcote	National	12862	19072	40.28%	54.45%	15964	13359	54.44%	Labour
Ōhariu	Labour	17084	16033	51.59%	65.76%	21205	11230	65.38%	Labour
Ōtaki	National	14569	20725	41.28%	55.45%	18083	14517	55.47%	Labour
Pakuranga	National	7777	22663	25.55%	39.72%	9653	15874	37.81%	National
Palmerston North	Labour	18388	11946	60.62%	74.79%	22823	8368	73.17%	Labour
Papakura	National	12780	20266	38.67%	52.84%	15862	14195	52.77%	Labour
Port Hills	Labour	22603	14687	60.61%	74.78%	28055	10288	73.17%	Labour
Rangitata	National	13663	19994	40.59%	54.76%	16958	14005	54.77%	Labour
Rangitīkei	National	10519	20809	33.58%	47.75%	13056	14576	47.25%	National
Remutaka	Labour	21725	13116	62.35%	76.52%	26965	9187	74.59%	Labour
Rodney	National	8579	28140	23.36%	37.53%	10648	19711	35.07%	National
Rongotai	Labour	21146	10246	67.36%	81.53%	26246	7177	78.53%	Labour
Rotorua	National	10887	18788	36.69%	50.86%	13513	13160	50.66%	Labour
Selwyn	National	9047	28686	23.98%	38.15%	11229	20093	35.85%	National
Tāmaki	National	8624	24026	26.41%	40.58%	10704	16829	38.88%	National
Taranaki-King Country	National	8595	23854	26.49%	40.66%	10668	16709	38.97%	National
Taupō	National	10276	24611	29.46%	43.63%	12754	17239	42.52%	National
Tauranga	National	10247	21499	32.28%	46.45%	12718	15059	45.79%	National
Te Atatū	Labour	16774	13590	55.24%	69.41%	20820	9519	68.62%	Labour
Tukituki	National	15467	18280	45.83%	60.00%	19198	12804	59.99%	Labour
Upper Harbour	National	10301	19857	34.16%	48.33%	12786	13909	47.90%	National
Waikato	National	9108	24560	27.05%	41.22%	11305	17203	39.65%	National
Waimakariri	National	11891	22657	34.42%	48.59%	14759	15870	48.19%	National
Wairarapa	National	13642	16514	45.24%	59.41%	16932	11567	59.41%	Labour
Waitaki	National	12054	24870	32.65%	46.82%	14961	17420	46.20%	National
Wellington Central	Labour	20873	10910	65.67%	79.84%	25907	7642	77.22%	Labour
West Coast-Tasman	Labour	18488	12895	58.91%	73.08%	22947	9032	71.76%	Labour
Whanganui	National	15045	16751	47.32%	61.49%	18674	11733	61.41%	Labour
Whangarei	National	7767	18734	29.31%	43.48%	9640	13122	42.35%	National
Wigram	Labour	17001	12407	57.81%	71.98%	21102	8690	70.83%	Labour

Of the regular electorates, this gives Labor 31; Nationals 29.

There are also the 7 Maori seats (mostly Labour v Maori Party contests); we have polling for each of these predicting Labour in all 7. We also have polling for one of our outliers, Northland (National win). Epsom Has been a consistent win for the ACT, while Ilam and Botany are both safe National seats (Botany will likely see there National-turned NZ Alliance replaced by another National rather than swinging with the politician, while Ilam had a strong lead for National over any other incumbent.

Of the electorates, then, the final prediction is Labour 38, National 32, ACT 1.

	Incumbent	Prediction
Auckland Central	National	Labour
Bay of Plenty	National	National
Botany	National	National
Christchurch Central	Labour	Labour
Christchurch East	Labour	Labour
Clutha-Southland	National	National
Coromandel	National	National
Dunedin North	Labour	Labour
Dunedin South	Labour	Labour
East Coast	National	Labour
East Coast Bays	National	National
Epsom	ACT	ACT
Hamilton East	National	Labour
Hamilton West	National	Labour
Hauraki-Waikato	Labour	Labour
Helensville	National	National
Hunua	National	National
Hutt South	National	Labour
Ikaroa-Rāwhiti	Labour	Labour
Ilam	National	National
Invercargill	National	Labour
Kaikōura	National	National
Kelston	Labour	Labour
Mana	Labour	Labour
Māngere	Labour	Labour
Manukau East	Labour	Labour
Manurewa	Labour	Labour
Maungakiekie	National	Labour
Mt Albert	Labour	Labour
Mt Roskill	Labour	Labour
Napier	Labour	Labour
Nelson	National	Labour
New Lynn	Labour	Labour
New Plymouth	National	Labour
North Shore	National	National
Northcote	National	Labour
Northland	National	National
Ōhariu	Labour	Labour
Ōtaki	National	Labour
Pakuranga	National	National
Palmerston North	Labour	Labour
Papakura	National	Labour
Port Hills	Labour	Labour
Rangitata	National	Labour
Rangitīkei	National	National
Remutaka	Labour	Labour
Rodney	National	National
Rongotai	Labour	Labour
Rotorua	National	Labour
Selwyn	National	National
Tāmaki	National	National
Tāmaki Makaurau	Labour	Labour
Taranaki-King Country	National	National
Taupō	National	National
Tauranga	National	National
Te Atatū	Labour	Labour
Te Tai Hauāuru	Labour	Labour
Te Tai Tokerau	Labour	Labour
Te Tai Tonga	Labour	Labour
Tukituki	National	Labour
Upper Harbour	National	National
Waiariki	Labour	Labour
Waikato	National	National
Waimakariri	National	National
Wairarapa	National	Labour
Waitaki	National	National
Wellington Central	Labour	Labour
West Coast-Tasman	Labour	Labour
Whanganui	National	Labour
Whangarei	National	National
Wigram	Labour	Labour