Labour spent $1.3 million and won 64 seats (which could rise to 65) and, with those half-million specials still to be factored in, has 1,171,544 list votes. In other words, the party spend $20,250 per electorate won, or $1.11 per vote.
NZ First, which clattered out of Parliament with zero seats got the wooden spoon. It spent $298,000 or $4.69 per vote for its 63,534 list votes. If the party did engage self-styled "Bad Boys of Brexit" Arron Banks and Andy Wigmore, it might want to ask for its money back.
The Greens were the most cost-effective, spending just $1990 per seat and 11c per list vote - but their numbers do inflate when social media is factored in (see below), there they spent four times as much as traditional media in September alone.
ACT also got strong bang-for-buck, albeit against a backdrop where it was always poised to make gains as David Seymour's euthanasia push gained majority support and the party benefited from disaffection with National on the right. It spent an average $27,270 per seat won (10) and $1.43 per vote.
Organic coverage and the new media war
Earlier, National leader Judith Collins complained that Labour got free publicity and kudos form Prime Minister Jacinda Ardern's regular appearances at 1pm Covid updates. But figures compiled by The Conversation showed Ardern's party also benefited from nearly double the organic (non-paid) interaction on social media - much of it driven by the PM's daily video chats on Facebook and Instagram.
During the campaign, AUT senior marketing lecturer Sommer Kapitan noted the "disarming, comfortable and relatable" Ardern had sky-high engagement rates against other influencers, let alone other politicians, providing her with an unmediated, direct line to voters. Some 22 per cent of Ardern's 1.4 million Instagram followers tuned in to watch a two-minute clip near the start of the campaign, where she joked about her messy house before weaving in a couple of campaign themes. During one of her Facebook livestreams on Covid, going into the second lockdown, 34 per cent of her 1.3m followers on that platform tuned in.
Kapitan says the Labour leader has mastered social media - and the free, organic marketing it can offer a savvy practitioner, in the same way US President Franklin Roosevelt used his radio "fireside chats" in the 1930s and 40s to explain policy to Americans. By the 1960s John F Kennedy had emerged as the original TV president after the first-ever televised debate (with Richard Nixon). In New Zealand, Rob Muldoon was the first politician to master the art of political TV.
Labour spent nothing promoting Ardern's Facebook and Instagram accounts for 1.1m interactions in September. National spent $35,409 promoting posts by Collins, which garnered 216,052 interactions.
Notably, Labour did splash out on its main Facebook and Instagram accounts between May and July - that is, before parties entered the four-month period before election day, when spending limits apply.
During that period, Labour spent $92,000 on social media to National's $25,100 and ACT's $14,200 (no other party spent more than $10,000).
Spending limits - and handouts
Spending limits apply to political parties over the four months leading up to the election - this year with a false start after the election was delayed a month to October 17.
Each party was allowed to spend up to $1.17 million of its own funds, plus $27,500 for every electorate where it stands a candidate (there are 72 electorates for the 2020-23 Parliament, which means a potential total spend of $1.98m at the electorate level).
On top of what they raise and spend off their own bat, the Crown allocated each party a set amount of funds for TV, radio and internet advertising around the 2020 election.
National - the largest party in terms of MPs in Parliament - got a $1.29m allocation, Labour $1.20m, the Greens and NZ First $311,000 apiece and Act $145,000 (see minor party allocations here).
Unregistered outside groups who want to try to influence the race can spend up to $13,200; those who register with the Electoral Commission up to $330,000.
Orange man spending - did it up participation?
And then there was the Crown.
In response to Herald questions, the Electoral Commission said its advertising budget for this year's election was $6.9m (versus $6.4m in 2014 and $6.1m in 2014).
There was also additional funding allocated in three areas:
• $2.6m for both referendums to raise awareness that the referendums are taking place, what the questions are, and how to take part
• $3.5m for Covid19 to inform the public of the safety measures at voting places and how people can vote if they cannot go to a voting place, and to lay the groundwork for advertising that could be used at short notice if circumstances changed
• $1.5m following the change of election date to inform people of the change in date and extend transactional and motivational advertising campaigns for another month.
The Commission declined to say, at this point, how much of its budget it spent on social media.
Participation by the under-30s has been notably lower than other demographics for the past few elections.
The Commission said $3.5m was ear-marked for "motivational" advertising, and its "don't be nervous about your first time" double-entendre effort was on high-rotate in the lead-up to the election.
"In our most recent Statement of Intent, a key performance measure was for 340,000 18- to 24-year-olds to be enrolled by the general election," an Electoral Commission spokeswoman told the Herald last month.
In the final wash-up, released this morning, 18-24 enrolment hit 351,271.
And all up, participation by the under-30s increased more than the population as a whole (though it should be noted that, beyond advertising, the Covid safety measure of extra voting places, making for easier voting, would have also played a role in increasing participation).
For 2020, 80.7 per cent of 18- to 29-year-olds were enrolled compared with 75.5 per cent at the last election in 2017.
That means younger voters still trail older by a wide margin - 91.2 per cent of 30-34s enrolled, and older demographics were all 96 per cent or more.
But the gap is closing.