Change was the most important issue of the 2015 federal election campaign, and the Liberals took full advantage of it to pull voters over to their side after the campaign began, according to the first polls of voters conducted since ballots were counted.

Polls conducted by Forum Research and, in British Columbia and Alberta, by Insights West shed some light on what was behind the motivations of the people who voted in this election campaign. They give a hint at what each of the parties did right and what they did wrong.

Though the Liberals won enough votes to push them into majority territory, the polls suggest their supporters were split on whether they were voting for a party or against another party. But change was the main issue for them, with 32 per cent telling Forum it was their main reason for voting for the Liberals. Leader Justin Trudeau was the main vote driver for 20 per cent of Liberals, while another 20 per cent said they voted for the party because it was the one they liked best.

The Liberals convinced a majority of their voters during the campaign itself, with two-thirds having decided to vote for the party after the election was called. The plan to go into deficits to spend on infrastructure moved the largest number of Liberal voters who swung to that party during the campaign, the polls suggest.

In British Columbia, where the Liberals made some of their most unexpected gains, strategic voting was also a big factor. According to Insights West, one-third of Liberal voters in B.C. said they would vote strategically. And like voters elsewhere in the country, the desire for change drove this decision.

Economy, security drove Conservative base

Throughout the campaign, Conservative support was stuck within a few points of 30 per cent. Why this was the case is demonstrated by some of the findings in the Forum poll: the majority of their voters (62 per cent) had already made up their mind to vote for the party before the election was actually called, and another 14 per cent had settled on their decision before Labour Day.

The numbers indicate the Tories were mostly only appealing to their base. Just 12 per cent of Conservative voters said they were voting against another party, which suggests that Stephen Harper may have made a strategic error in going after the Liberals so aggressively at the tail end of the campaign.

Conservatives were the most likely to say that the party itself was what they were voting for, and Forum suggests that the party was much more important than the party leader in influencing Conservative voters' decisions, by a margin of 42 per cent to 25 per cent.

For 45 per cent of Conservative voters, jobs and the economy was the issue with the most effect on how they cast a ballot. The next most important issue was national security and terrorism at 20 per cent, aligning with the focus of the Conservative campaign.

But what of the niqab? It was the decisive issue for only 5 per cent of all voters, and scored highest as a major factor in Quebec and Alberta. But it did move votes. According to Forum, 14 per cent of Quebecers who changed their mind during the campaign did so because of the Conservative stance on the niqab.

New Democrats vote strategically, but not for Mulcair

More NDP voters told Forum that they were voting primarily against a party than for a party, suggesting that many voters who went with the New Democrats did so for strategic reasons. Indeed, 44 per cent of NDP voters in B.C. and 40 per cent in Alberta said that they were voting strategically, according to Insights West. This may explain why the New Democrats managed to make gains in British Columbia despite dropping in the share of the popular vote from their 2011 showing.

Like the Liberals, change was a major driver for NDP voters. But voting for the local candidate scored much more highly among New Democrats than it did among Liberals and Conservatives, while voting for the leader scored much lower. Forum found that just 9 per cent of NDP supporters were influenced most by the leader in their voting decision, less than half of the scores for Justin Trudeau and Stephen Harper. Not surprisingly, by the end of the campaign Tom Mulcair was trailing both Trudeau and Harper by a wide margin on who would make the best prime minister.

These numbers lay out a clear view of how the campaign was won and lost by the three parties.

Both the Liberals and New Democrats were jostling to be that agent of change, but the Liberals had the policy winner in their infrastructure spending and the leader to get the message through to voters. The New Democrats were hobbled by strategic voting nationally and a leader that was not a source of great appeal for the party, though local candidates and localized strategic voting may have won them some seats.

The Conservatives, meanwhile, were unable to gain new voters outside of their base, and were powerless against the change narrative that, by the campaign's end, had supplanted the economy as the top issue for Canadians.

The poll by Forum Research was conducted for the Toronto Star and interviewed 1,451 Canadians via interactive voice response between October 20 and 21. The margin of error associated with the survey is +/- 3 per cent, 19 times out of 20.

The polls by Insights West were conducted for the Vancouver Sun, the Calgary Herald, and the Edmonton Journal via the Internet between October 18 and 19, interviewing 623 British Columbians and 605 Albertans. As the polls were conducted online, a margin of error does not apply.