This Gazette quote pretty well sums it up:

Polls completely missed the NDP wave that swept Quebec in the last federal election, predicted the Liberals were toast in the 2012 Quebec provincial election and were defied in last year’s B.C. election, in which the Liberals — not the favoured NDP — won a majority.

“They have bungled three elections in a row,” said Daniel Weinstock, a McGill University law professor. “So unless they have really revamped their tools, perhaps we don’t have as clear an idea as we think of where we are.”