19,500 invalid health board votes in three years, but expert says STV not the problem

More than 19,500 votes were invalid in the past three Bay of Plenty District Health Board elections.

The district health board uses Single-Transferrable Vote (STV), a method of voting Tauranga City Council is switching to this year.

But the city's electoral officer says invalid votes are largely caused by having a mix of voting methods on a single paper, not STV itself.

In previous elections, Tauranga City Council used First Past the Post, where voters give the candidate of their choice for each seat a tick. Those with the most votes, win.

It's also the method the Bay of Plenty Regional Council uses.

At the 2016 elections, less than 1 per cent of city and regional council votes in Tauranga were judged invalid, according to statistics provided by electoral officers in the Bay of Plenty.

But almost 5 per cent of votes case in the health board election were invalid. Over the past three elections, 19,643 votes out of 157,851 were invalid.

In 2010, 7278 votes were invalid, rising to 9574 in 2013 before plummeting to 2791 in 2016.

Health boards have been mandated by law since 2004 to use STV, where voters rank the candidates.

Tauranga City Council electoral officer Warwick Lampp said the main problem with mixed ballots was that voters just kept ticking.

"They start with the mayoralty and give a tick. At-large councillors: ticks. Ward councillors: ticks. Regional councillors: ticks.

"Then the DHB was on the last page. People just kept ticking," Lampp said.

This year, he predicted the statistics would change because the city council and DHB were using STV and Tauranga's regional councillors - bar two vying for the Mauao Māori seat - have been elected uncontested so no votes are required.

"So the number of invalids should be bugger all."

He was predicting less than 1 per cent.

"What the statistics show is that when a council is STV, the DHB blanks and invalids go down because it's the same system."

Dale Ofsoske, the electoral officer for the Bay of Plenty District Health Board, said votes under STV were invalid when the voter did not use a number to rank the candidates - using a tick instead, for example.

A vote could also be invalid if the voter did not start with a 1 or counters were not able to decipher how a voter voted.

"The number of invalid votes generally decreases if all organisations use the STV electoral system and also as time progresses, the more voters become familiar with the STV electoral system."

Priya Kurian, a professor of political science and public policy at Waikato University, said that although STV was unlikely to increase voter turnout, it could change the results.

"Research shows that a more proportional voting system such as STV helps a more diverse pool of candidates get elected."

Under STV, fewer votes were "wasted", she said. Seats were awarded proportionally rather than a "winner takes all" scenario of First Past the Post.

"So we can expect strong candidates who are traditionally under-represented, such as women, people from ethnic minorities and youth, for example, to be more successful."

- Voting documents will be delivered to enrolled voters from Friday. Deliveries should be done by Wednesday. Voting is by postal ballot and is open until midday on October 12.

Hack your vote: Strategy in STV

Let's say there is a candidate you absolutely don't want elected.

Under First Past the Post your options were simple - give your tick to someone else.

But under STV, you have options. Would it be better to stick them at the bottom of your ranking, or give them no ranking at all?

Tauranga electoral officer Warwick Lampp said the official advice was that voters should rank as many candidates as they wish, in whatever order they choose.

But he said there were strategies voters could apply if they wanted to ensure the full weight of their vote supported a specific outcome.

In STV, each person's vote is split into the number of rankings they chose to give. The higher the ranking, the more weight given to each piece of the vote.

Seats were then awarded proportionally, so even a low rank may contribute towards someone getting elected.

So to ensure you don't help someone you don't support get elected, Lampp said it would be better to give them no ranking over a low ranking.

The same would go if you have a solid favourite, and no regard for the rest.