Tim Hudak was forced to defend his "Million Jobs Plan" Wednesday as a growing number of economists questioned the math behind the Ontario Progressive Conservative leader's promise, which is the centrepiece of his election platform.

Despite being hammered repeatedly on the issue, Hudak was adamant that the PC figures were right.

"I stand behind our numbers," he said at a furnace-making facility in Niagara Falls, Ont. "I simply believe that permanent tax reductions on job creators, more affordable energy is going to create jobs."

Hudak has promised a PC government would bring a million jobs to Ontario over the next eight years, although about half of those would be created through normal economic growth, regardless of which party is in government.

First the Liberals, and then a number of prominent economists, including a former federal associate deputy minister of finance, have poked holes in Hudak's numbers. They focus, in particular, on the possibility that the Tories misinterpreted information from a Conference Board of Canada report commissioned by the PCs.

"A number of highly respected independent economists have gone through Tim Hudak's plan. They have said that it is riddled with errors," Liberal Leader Kathleen Wynne said. "I think it's pretty clear that Tim Hudak and his team got it flat wrong."

Person years employment or jobs

Recently penned columns by a few economists have questioned the Tory math, with particular attention on the PCs' use of the Conference Board of Canada report.

The Conference Board uses the term "person years of employment" in its projections. The economists suggest the Tories have confused that with permanent jobs, resulting in a vast overestimation of just how many new positions their plan for the province would create.

Michael Veall, an economics professor at McMaster University believes the error is an accident — but a serious one.

Essentially, each new permanent job that would be created under the Million Jobs Plan was counted eight times rather than just once.

"I'm confident it wasn't intentional, it was just an accident," he said. "I'm not judging overall competence, but it is a very serious error. I believe it was a genuine, unintentional error, but obviously it would be better if we were talking about other issues instead of an error in a program."

Party officials told reporters that they had used some data sources that dealt in person years of employment, along with others that measured employment in different ways to come up with the jobs figures in their platform.

Mike Moffatt, an economist with Western University's Ivey School of Business, is among those who've written columns critical of what he calls the Tories' apparent misinterpretation.

"Most of their numbers are eight times multiplied," he said, agreeing the PCs appeared to have counted a person working in a single job over eight years as a separate job for every year of their plan.

"This in no way can be considered a million jobs plan ... It's clear that the Tories misinterpreted these reports."

Moffatt also believes the PCs simply made a mistake. He said their math speaks to competency.

"If you can't get something this small right, then what does that mean for the bigger picture for the rest of the platform?" he said.

Moffatt said that while approximately 500,000 jobs were likely to be created anyway, "the remaining 300-400,000 now become closer to 50,000."

"They're off by about 350,000 jobs here," he said.

Math or ideology

Ontario NDP Leader Andrea Horwath derided the PC jobs plan Wednesday. "I don't think anybody can make heads nor tails of what Mr. Hudak is proposing." (Aaron Vincent Elkaim/Canadian Press) Veall said the opinions of the economists questioning the math are not based on ideology.

"It's much closer to arithmetic," he said. "It is economists of different backgrounds who are pointing this same thing out."

Hudak, however insisted his party's calculations were sound.

"We strongly disagree with that interpretation. I think that the economics is straightforward," he said. "Permanent reductions on taxes on job creators and on families mean permanent jobs."

NDP Leader Andrea Horwath seized on the questions about the plan Wednesday.

"I don't think anybody can make heads nor tails of what Mr. Hudak is proposing,” Horwath said.