Roy Morgan Poll most accurate on NZ Election – predicting a ‘crushing’ Labour majority for PM Jacinda Ardern
The most accurate poll of the weekend’s New Zealand Election was the final Roy Morgan New Zealand Poll which predicted a ‘crushing’ victory for Prime Minister Jacinda Ardern and a governing majority for the Labour Party.
The official results show the Labour Party with 49.1% of the Party Vote finishing well ahead of National on 26.8%, Act NZ on 8%, the Greens on 7.6% and NZ First on only 2.7%.
The final Roy Morgan New Zealand Poll released two days before last Saturday’s election showed the Labour Party with a Parliamentary majority winning lead on 47.5% - closer than the final polls for both 1 News Colmar Brunton (46%) and Newshub-Reid Research (45.8%).
Roy Morgan predicted National support of 28.5% which was significantly closer to National’s election result of 26.8% than either Newshub-Reid Research (31%) or 1 News Colmar Brunton (31.1%).
All three polls under-estimated the extent of Labour’s support and over-estimated support for National but the average error for the two major parties was only 1.65% for Roy Morgan compared to 3.65% for 1 News Colmar Brunton and 3.8% for Newshub-Reid Research.
Roy Morgan was also closest when considering the results of smaller parties such as Act NZ and the Greens and minor parties such as the Maori Party and The Opportunities Party (TOP).
Roy Morgan’s average error across all parties was only 0.9% compared to an average error of 1.1% for 1 News Colmar Brunton and 1.4% for Newshub-Reid Research.
See below for a full table comparing the final polls of Roy Morgan, 1 News Colmar Brunton and Newshub-Reid Research with the final election result.
Roy Morgan CEO Michele Levine says:
“The final Roy Morgan New Zealand Poll of the 2020 ‘COVID-19’ New Zealand Election was the most accurate final pre-election poll (‘Prime Minister Jacinda Ardern set to sweep to a ‘crushing’ election victory on Saturday’ – October 15, 2020) and correctly predicted a historic majority for Jacinda Ardern’s Labour Government – although all major polls predicted a comfortable Labour victory.
“The average error of the final Roy Morgan New Zealand Poll was only 1.65% for the two major parties – less than half the error for the final pre-election polls of both 1 News Colmar Brunton (3.65%) and Newshub-Reid Research (3.8%).
“Not only was the final Roy Morgan New Zealand Poll ‘closest to the pin’ for the major parties but it was also most accurate when considering support across the board for the major parties as well as smaller parties such as the Greens, Act NZ, NZ First and the Maori Party with an average error of only 0.92%.
“The Australian’s Adam Creighton picked up on Roy Morgan’s polling for New Zealand and noted last Friday that ‘Jacinda Ardern, New Zealand’s young, glamorous Prime Minister (was) bound for a historic election victory… (and was) within a ‘whisper’ of winning an outright majority in NZ’s parliament according to recent Roy Morgan polling’ – Creighton was proved correct the Labour Party securing a majority of 64 seats in the 120 seat parliament.”
New Zealand Voting Results – 2020 New Zealand Election
Ranking the Final Polls of the 3 Major Pollsters: Roy Morgan, Newshub-Reid Research & 1 News-Colmar Brunton
| PARTY | 2020 NZ ELECTION | ROY MORGAN | DIFFERENCE | NEWSHUB-REID RESEARCH | DIFFERENCE | 1 NEWS COLMAR BRUNTON | DIFFERENCE |
| Sample size | 911 | 1,000 | 1,005 | ||||
| Interviewing period | Oct. 1-17, 2020 | Sep. 1-27, 2020 | Oct. 8-15, 2020 | Oct. 10-14, 2020 | |||
| Result | % | error | % | error | % | error | |
| Labour | 49.1% | 47.5% | +1.6% | 45.8% | +1.7% | 46% | +3.1% |
| National | 26.8% | 28.5% | -1.7% | 31.1% | -4.3% | 31% | -4.2% |
| Act NZ | 8.0% | 7.0% | +1.0% | 7.4% | +0.6% | 8.0% | - |
| Greens | 7.6% | 9.5% | -1.9% | 6.3% | +1.3% | 8.0% | -0.4% |
| NZ First | 2.7% | 2.5% | +0.2% | 3.5% | -0.8% | 2.6% | +0.1% |
| Maori | 1.0% | 0.5% | +0.5% | 0.6% | +0.4% | 0.6% | +0.4% |
| TOP | 1.4% | 1.5% | -0.1% | 1.3% | +0.1% | 1.1% | +0.3% |
| Others | 3.4% | 3.0% | +0.4% | 4.0%* | -0.6% | 2.7%** | +0.7% |
| Average error (Major Parties) | 1.65% | 3.80% | 3.65% | ||||
| Average error (All Parties & Others) | 0.92% | 1.42% | 1.15% |
*Newshub-Reid Research Poll had Others including New Conservative Party (1.7%) and Advance NZ (0.3%).
**1 News Colmar Brunton Poll had Others including New Conservative Party (1.5%), Advance NZ (0.9%) and ONE Party (0.2%).
Final Roy Morgan New Zealand Poll: https://www.roymorgan.com/findings/8543-nz-national-voting-intention-september-2020-202010142349
Final Newshub-Reid Research Poll: https://www.newshub.co.nz/home/politics/2020/10/nz-election-2020-newshub-reid-research-poll-shows-labour-with-slim-majority-as-national-makes-slight-gain.html.
Final 1 News Colmar Brunton Poll: https://static.colmarbrunton.co.nz/wp-content/uploads/2019/05/10-14-October-2020_1-NEWS-Colmar-Brunton-Poll-report-1.pdf
Margin of Error
The margin of error to be allowed for in any estimate depends mainly on the number of interviews on which it is based. Margin of error gives indications of the likely range within which estimates would be 95% likely to fall, expressed as the number of percentage points above or below the actual estimate. Allowance for design effects (such as stratification and weighting) should be made as appropriate.
| Sample Size | Percentage Estimate |
| 40% – 60% | 25% or 75% | 10% or 90% | 5% or 95% | |
| 1,000 | ±3.0 | ±2.7 | ±1.9 | ±1.3 |
| 5,000 | ±1.4 | ±1.2 | ±0.8 | ±0.6 |
| 7,500 | ±1.1 | ±1.0 | ±0.7 | ±0.5 |
| 10,000 | ±1.0 | ±0.9 | ±0.6 | ±0.4 |
| 20,000 | ±0.7 | ±0.6 | ±0.4 | ±0.3 |
| 50,000 | ±0.4 | ±0.4 | ±0.3 | ±0.2 |
