The Claim: "The Green Party [has] followed through on its promise to present Canadians with a detailed accounting of the new spending and revenue measures outlined in the party's 2019 Platform."

-- A Green Party media release, Sept. 25th.

The Facts:

On Wednesday, the Green Party released an eight-page document breaking down the economic costs and benefits of its election promises running through the 2023-24 fiscal year, becoming the first federal party to attach a price tag to its program.

The overview projects $62.2 billion in new government revenue and $69.9 billion in "spending changes" in 2020-21, with an overall $22.7 billion deficit. But the party claims that it will shrink the deficit by $10 billion the following year, and be running a $401 million surplus by 2023-24.

The document also provides budget details for 16 revenue changes, ranging from capital gains adjustments to a wealth tax, and 86 spending promises including universal pharmacare, free post-secondary tuition and the elimination of student debt, and the development of a national food waste strategy.

However, a number of other major party promises — like phasing out oilsands production, increasing the federal carbon levy by $10 a year after 2022, and a guaranteed "livable income" for older and out-of-work Canadians — were not included in the estimates.

To date, the Parliamentary Budget Officer (PBO) has released its own costing for 23 of the Green Party's platform promises — 13 of the revenue changes and 10 of the spending proposals.

More Green promises have been vetted

In that regard, the Greens are way out in front. As of Thursday afternoon, the PBO has vetted 13 Conservatives promises, and four from the New Democratic Party. No Liberal Party pledges have been independently costed. Ditto for the Bloc Québeçois, and the People's Party of Canada.

What the PBO determined however, might make the Greens wish they never bothered. Ten of the party's price tags are rated as having "moderate uncertainty," and the remaining 13 are rated as having "high uncertainty."

Take the party's pledge to create a new, 0.5 per cent tax on all financial transactions in Canada, for example. The Greens claim that it will raise $15.7 billion in new revenue in 2021-22 and $18.1 billion a year by 2024-25 — the single biggest tax increase they are counting on to finance their ambitious plans.

But according to the PBO, the response of the financial markets to such a tax is so unclear that the revenue estimates "could be off by factors of 2 or 3 in either direction (higher or lower)."

Big windfall? Huge hole? Dead on? Who knows?

Outside assessment gives failing grade

Other outside assessments of the Green platform pricing are even harsher.

The Institute of Fiscal Studies and Democracy (IFSD) at the University of Ottawa has issued a "Fiscal Credibility Assessment" and gives the Green Party a failing grade when it comes to realistic economic assumption, responsible fiscal management, and transparency.

Kevin Page, the former parliamentary budget officer who heads the institute, says the Green Party costing is riddled with errors — for example the numbers in the detailed tables don't match the overview totals. And it all appears to be based on outdated, 2018 fiscal projections.

"To us, it looked like it was put together in a very hurried fashion," says Page. "Somebody made a mistake."

Page gives the party credit for asking the PBO to cost out many of its "toughest measures." But he says that Elizabeth May's proposals on the move to a zero-carbon economy and rebalancing the tax system are so transformative that much more detail is required before they can be fairly assessed.

The Green Party has acknowledged the errors and omissions and says it is working to correct them.

Greens say revisions coming

"We are currently undertaking a review and will present a revised version in due course," Rosie Emery, a party spokesperson, said in an emailed statement.

But the public shouldn't expect any more independent analysis. Emery says that the PBO has now released all of the Greens' requested costing estimates.

(It also seems likely that the Greens have used up their allotted share of the resources and money that the Parliamentary Budget Officer dedicated to studying election promises. And with a little more than three weeks to go before ballots are cast, the PBO's "absolute deadline" for new requests — 15 business days before the election — is looming.)

Geneviève Tellier, a University of Ottawa political scientist who studies budgetary policies and public finances, says the PBO costing — a new wrinkle for a federal election campaign — is working better than she expected; providing a level of detail about party promises and their underlying assumptions that voters have never had before.

Small parties at a disadvantage

But the new system may not be working in the Greens' favour.

"A smaller party may be disadvantaged," says Tellier, noting their relative lack of in-house expertise and money. "The bigger parties are better able to manipulate their numbers, or try to present them to their own advantage."

In other words, honesty may be the best — but not the most politically sophisticated — policy.

The Verdict: Partially true. The Greens have shared more information about their promises than any of the other federal parties, thus far. But errors in their math, and a number of big, unpriced pledges, make their claim of complete transparency a little cloudy.



Sources: Green Party releases costing of platform initiatives, Green Party of Canada ; Platform 2019 Costing, Green Party of Canada ; 2019 Election Proposal Costing PBO Estimates, Office of the Parliamentary Budget Officer ; Implement a new financial transaction tax, Office of the Parliamentary Budget Officer ; Fiscal Credibility Assessment : Green Party of Canada Platform 2019 Costing, Institute of Fiscal Studies and Democracy ; Estimating the financial cost of election campaign proposals: a framework, Office of the Parliamentary Budget Officer .

More from CBC News

WATCH - From The National, Elizabeth May says Trans Mountain support means no Green backing in minority government: