Brian Gallant's Liberals started election day with a head start when New Brunswickers headed to the polls on Sept. 24. His party had won the most votes and was leading in the most seats after two days of advance voting had completed.

But by the end of election day, inroads made by the Greens — and to a lesser extent the People's Alliance and New Democrats — turned his two-seat edge into a one-seat deficit.

According to data published by Elections New Brunswick and analyzed by CBC News, the Liberals took 41.1 per cent of ballots cast in the advance voting that occurred on Sept. 15 and 17, compared with 33.4 per cent for the Progressive Conservatives under Blaine Higgs, 11.1 per cent for the People's Alliance, 9.6 per cent for the Greens and 4.2 per cent for the New Democrats.

This translated into the Liberals ending the two days of advance voting with a lead in 24 seats, one short of the 25 needed to form a majority government. The PCs led in 22 seats, the People's Alliance in two and the Greens in just one — that of leader David Coon.

The Liberals also won the most votes cast on election day, but their share of that vote fell by 4.3 points to 36.8 per cent. The PCs took 31.5 per cent of the votes cast on Sept. 24, representing a drop of 1.9 points.

The three smaller parties all took more of the votes cast on election day than they did in the advance polls, with Kris Austin's People's Alliance taking 13 per cent, the Greens 12.6 per cent and the New Democrats 5.3 per cent.

Both the People's Alliance and the NDP saw modest increases in their popular vote share — 1.9 and 1.1 points, respectively. The Greens, however, jumped three points.

That made the difference in Memramcook-Tantramar and Kent North. The Greens trailed the Liberals in both ridings in the advance voting, but won enough of the vote on election day to move ahead and win the seats.

The Liberals also lost Riverview and Oromocto-Lincoln-Fredericton to the PCs on Sept. 24, after starting the day with the lead.

Saint John-Harbour, however, flipped from the PCs to the Liberals on election day.

Strong results in the advance voting saved the PCs in two ridings — Shippagan-Lamèque-Miscou and in Southwest Miramichi-Bay du Vin. The Liberals won more votes in the former and the People's Alliance in the latter on election day, but the lead the PCs built in the advance voting was wide enough to keep them ahead when the counting was over.

Those victories ensured that Higgs came out of the night with one more seat than Gallant.

How it may have happened

That wasn't the case in Fredericton-York, however. The People's Alliance won enough votes on election day to erase the lead the PCs had there in the advance polls.

A number of factors could have contributed to the shift in the results between the advance polls and election day.

Parties put a lot of effort into getting their supporters to cast their ballots early in order to lock those votes in. The Liberals and PCs would have had more resources to do that than either the People's Alliance or Greens.

Public opinion polls also suggested that the two smaller parties had made significant gains in support over the last week of the campaign, while the Liberals and PCs fell back.

And voters who were on the fence between the older parties and the two upstarts might have been waiting until election day to finally make up their mind.

Different pattern than in 2014

Some of the trends between the advance polls and election day voting were the same as in 2014's provincial election.

The Liberals won 46.5 per cent of the vote in the advance polls that year before their vote dropped to 41.9 per cent on election day. The Greens increased their vote share by 2.7 points to 7.1 per cent on election day in 2014, while the New Democrats increased theirs by 1.6 points to 13.3 per cent.

But the PCs and People's Alliance went in different directions on election day in 2014. The PCs saw their support increase by 0.5 percentage points to 34.7 per cent, while the People's Alliance vote fell by 0.3 points to 2.1 per cent.

This means the voting patterns identified in 2018 were in some degree unique to this campaign.
And with such a close result, those patterns suggest the last days of the campaign might have made all the difference.