The group representing Canada's statisticians is calling on the Conservative government to reverse its decision to replace the mandatory long census with a voluntary survey.
The Statistical Society of Canada wrote to Industry Minister Tony Clement on Friday "in the interests of maintaining the high quality of information" for which Statistics Canada is famous.
"We view it as surprising that decisions are made limiting the ability of experts at Statistics Canada to carry out a mandate for the benefit of Canadian policy makers, educators, small business and science without consulting these same experts," the letter says.
"We respectfully submit that, in the interests of both cost and retention of the Canadian reputation for the quality of statistical information, the decision to replace the long form by a voluntary survey be revisited, reinformed and reversed."
The letter was signed by the president of the statisticians' society, Don McLeish, his predecessor, his successor-to-be and the head of the American Statistical Association.
The former chief statistician of Canada, Ivan Fellegi, has also spoken out against the decision.
Mr. Fellegi and his colleagues, along with economists and planners, have said the numbers will carry a bias because certain groups of Canadians are unlikely to fill out the form.
Mr. Clement has said the decision was based on an unspecified number of complaints about the coercive and intrusive nature of the census process. Those refusing to complete the form faced prosecution and fines.
The statisticians say it's evident the decision wasn't made to save money: the new plan is for a voluntary questionnaire to be sent out to 33 per cent of households rather than the 20 per cent before.
If a reasonable number of the survey forms are returned, it will cost "far more" than the mandatory long-form census, they warn, "while the information provided is subject to substantial bias and likely of little use to policy makers."
"Is it unreasonable for the Canadian government to obtain unbiased statistical information in areas critical to planning for the future of Canada - business and trade statistics, the aging population, education and income?" they ask.
"Should those who collect and spend our tax dollars on matters determined to be in the public interest not do so with the most informed statistical information possible?"
Voluntary census forms are like voluntary tax forms, they write.
"Those who return them can hardly be expected to accurately represent those who do not."
That's why filling out the census is mandatory under the Statistics Act, they say.
Meanwhile, national Inuit leader Mary Simon called on Ottawa to reconsider its decision, saying it will diminish the availability of comparable data between aboriginals and other Canadians.
"In our long-term goal of closing the gaps in health, education, and economic conditions among our people and communities and other Canadians, building long-term comparable data is a key element," she said in a statement.
"This ill-conceived cabinet decision impacts our ability to work towards that goal."
The long-form census is a key tool in understanding populations and assessing the conditions in which aboriginals live, she said, "including the level of social disparity." Without the long-form census, "our current data systems will be severely disabled."
Added Ms. Simon: "Canada prides itself on the quality and completeness of its census process. Statistics Canada does not take a back seat to any similar agency in the western world. This decision is clearly a step backwards for Inuit and the Canadian census."