Harper and Trudeau continue to be tightly locked in the weekly preferred Prime Minister tracking by Nanos.

Thirty-one per cent of Canadians prefer Harper as PM, 31 per cent also prefer Trudeau as PM, while 18 per cent prefer Mulcair, 5 per cent prefer May and 14 per cent were unsure. The past two weeks have been a close tussle between Harper and Trudeau on this measure.

On the Nanos Party Power Index itself, the federal Liberals are at 57 points out of 100 followed by the Conservatives at 51 points, the NDP at 49 points, the Green Party at 32 points and the BQ at 27 points (QC only).

The Nanos Party Power Index methodology is comprised of a basket of political goods that includes ballot preferences, accessible voters, preferred PM views and evaluations of the leaders. It is modeled similar to a standard confidence index.

The Liberal advantage in the Nanos Party Power Index is fuelled by their high level of accessible voters compared to the other federal political parties. Asked a series of independent questions for each federal party, 58 per cent of Canadians would consider voting Liberal, 46 per cent would consider voting NDP, 43 per cent would consider voting Conservative, and 29 per cent would consider voting for the Greens.