Vote Intention Poll Performance: New Zealand General Election 2020

How did the pre-election polls for the 2020 Parliament perform?

On 17th October 2020, New Zealand electors cast votes for the new Parliament. The COVID-19 pandemic delayed this election.

How well did the pre-election polls perform? This article discusses their accuracy.

Final Polls

Three research companies conducted vote intention polls during the election campaign. The last poll finished on 15th October 2020 — two days before the election.

According to the Electoral Commission, Labour took 49% of party votes. In preliminary results, the National Party had 27% of party votes. ACT New Zealand finished third, on 8% of party votes.

This is the preliminary results. (Image: NZ Electoral Commission)

To measure accuracy, I look at:

• LAB Lead: Labour minus National party vote intention shares, deducting the actual difference.
• Two-party mean absolute error: the average absolute difference between estimates and actual shares. This is for vote intention share estimates of Labour and National parties.
• Five-party mean absolute error: the calculation extends to NZ First, ACT, and Greens.