A rookie polling firm that claimed Manitoba's election campaign is close now says it made a mistake and the Progressive Conservatives are well ahead of all other parties heading into the provincial vote on Sept. 10.

On Friday, Converso Research issued a poll claiming the PCs and NDP are in a "dead heat" in Manitoba.

CBC Manitoba published the results on Saturday. Veteran pollsters quickly cast doubt on the claim, which diverged widely from previous polls that placed the PCs well ahead.

Later on Saturday, Converso issued a statement citing a problem with its own data and promising a review.

On Monday, it issued a correction statement suggesting its poll should have concluded the PCs are in fact well out in front in Manitoba.

"The discrepancy was caused by an over-weighting of responses from northern Manitoba," Converso managing director Carl Mavromichalis said in the statement, citing a third-party review of its work.

"We apologize for the error and recognize the importance of providing Manitobans with an unbiased, independent election survey. We feel confident that we have now fulfilled our intention."

Converso now claims the PCs enjoy the support of 35 per cent of Manitoban voters, compared to 21 per cent for the NDP, 12 per cent for the Liberals, eight per cent for the Greens and one per cent for other parties — while undecided, non-responsive and unwilling voters accounted for 22 per cent of the response.

Converso's Mavromichalis did not immediately respond for requests for comment from CBC News to further explain the discrepancy.

The uncommissioned, interactive voice response (IVR) poll was the first public opinion research survey conducted by Converso Research. It surveyed 1,127 Manitobans between July 28 and Aug. 7.

IVR polling typically employs a recorded voice in place of live interviewers. Callers respond to questions by either pressing phone keys or by responding with voice answers that are recorded for later analysis.

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