A year ago, some observers were wondering when Prime Minister Stephen Harper would step down in order to avoid defeat in the next federal election. Now, pundits are debating whether the PM can win a record fourth election when Canadians are next called to the polls.

What has changed?

The fortunes of the Conservative Party have improved, as the Tories move into a close race with Justin Trudeau's Liberals after trailing by a significant margin for most of the last two years. Much of that rosier picture can be credited to an increase in Canadians' approval of Harper.

Granted, it is important to keep things in perspective. The Conservatives still sit behind the Liberals in most polls and are a great distance from where they need to be to win a majority government. Nevertheless, that is a far cry from where the party stood a year ago, when the Conservatives were in more danger of being overtaken by the third place New Democrats than they were a threat to the Liberal lead.

Recent polls have shown higher approval ratings for Harper than he has experienced at any point since Trudeau arrived on the scene in April 2013. December polls by Forum Research, EKOS Research, and Angus Reid Global all showed gains over where Harper stood in the spring of 2014, worth anywhere from two to 10 points.

If we group approval ratings polls by quarter and average them, we get a clear picture of how Harper's numbers have been on the upswing (undecideds have been removed from the calculation in order to compare apples to apples, because different methodologies tend to produce different rates of undecideds, and some pollsters do not provide the option at all).

Quarterly polling averages measuring Stephen Harper's approval rating, after the removal of undecideds. (Éric Grenier)

In the last quarter of 2014, Harper averaged an approval rating of 39 per cent, his best showing since the first quarter of 2013. And he has shown consistent growth since falling to a low of 32 per cent in the last quarter of 2013, when the Senate scandal was at its height.

His average disapproval rating stands at 61 per cent. That is still quite high, and compares poorly to the average fourth-quarter (decided) approval ratings of NDP Leader Tom Mulcair (59 per cent) and Trudeau (54 per cent). But Harper's disapproval rating is roughly equal to the number of Canadians who did not vote for his party in 2011, when it won a majority of seats.

Renewed approval in Ontario

The most consequential improvement in the prime minister's approval rating has occurred in Ontario, where both Forum and EKOS have shown better numbers than where Harper was last spring. A recent Ipsos Reid poll even showed a majority of Ontarians approving of him.

An Abacus Data poll looking at impressions, rather than approval, found that 37 per cent of Ontarians hold a positive impression of Harper, versus 32 per cent who hold a negative view. The opposite was the case in two similar polls by Abacus in the summer, when Harper averaged a 31 per cent positive impression in the seat-rich province against 39 per cent negative.

Regional gains have been recorded in approval ratings and Abacus's impression numbers throughout the country, particularly in British Columbia and the Prairies. Harper's numbers have even improved in Quebec, though from a very low base.

These improvements have also been reflected in polls asking who Canadians prefer for the top job. Nanos Research's weekly surveys put Harper at around 33 per cent in December. He was at just 27 per cent a year before.

So, the numbers suggest Harper has improved his chance of re-election in this year's federal vote. But the odds might still be stacked against it. His approval ratings, while better than before, continue to lag those of Trudeau and Mulcair. His party is still behind the Liberals in most polls.

On current trends, the Conservatives would win only a narrow minority government that may not survive long into 2016. But the prime minister appears to no longer be the drag on his party that he might have been a year ago.

This article uses averages derived from dozens of polls carried out over the last two years, all of which differ in terms of methodology, sample size, and field dates. These surveys have not been individually verified by the CBC.

The poll by Abacus Data was conducted between Dec. 18 and 20, interviewing 1,438 Canadians via the internet. As the poll was conducted online, a margin of error does not apply. The question asked was as follows: "Do you have a positive or negative impression of the following people?"