If I tried to write down in detail the answer to the question you have posed, I don't think I would do a better job than the answer posted by Mr. Alex Himelfarb, a previous Clerk of the Privy Council.
With your permission, Chair, I'll just try to read that answer in response to the question. He said, and I'm just going to quote the whole thing from him verbatim, the following:
In Canada, our professional, non-partisan public service has traditionally been guided by the principle of “fearless advice and loyal implementation.” This is based on the belief that governments work best when they have access to the best possible information, options, and advice—including what they may not wish to hear—and, in the end, democracy demands that the public service implement loyally whatever lawful decision the elected government of the day makes—whether the public servants agree or not. That's how it works when it works. I know Munir to be a man of great integrity, committed to the value and values of a professional, non-partisan public service....
Munir also had another responsibility as Canada's Chief Statistician and that is to protect the integrity and credibility of the agency and its products without which Statistics Canada cannot deliver its mandate. In Munir's introduction to the Statistics Canada website he spoke with evident pride of the objectivity and neutrality of the agency's data. Statistics Canada, which has earned a sterling international reputation, has long understood that it can do its job of informing public and private decisions and supporting democratic accountability only if people trust in its integrity and technical competence.
I have not yet had the opportunity to talk with Munir but I imagine that this is why he felt it necessary, when doubts arose about what Statistics Canada advised, to acknowledge publicly that the voluntary approach he was to implement is not a substitute for the mandatory survey. No Chief Statistician would want people to lose trust, to think that Statistics Canada compromised its technical advice to the government or would, in any way, misrepresent the information it provides to Canadians. This goes to the heart of the agency's credibility and of the values of public service.