OTTAWA - The former head of Statistics Canada was set to speak out about the Harper government's controversial census change just before he abruptly quit his post, newly released documents show.

The papers reveal that Munir Sheikh was going to tell his staff that data from a voluntary long-form survey would not be as useful as the current mandatory form.

The documents also show that the government tried to shape the statistics agency's public comments on the matter.

"Many of you have asked whether I believe the National Household Survey will satisfy the needs of all users of the previous long form," says a draft text of Sheikh's planned speech to staff.

"My response is that the NHS will meet the needs of many users but will not provide useful data to meet the needs of other users of the mandatory long-form census data."

The remarks appear to have been emailed to the Privy Council Office and Industry Canada in the wee hours of the morning on July 21.

They were contrary to what the public had been led to believe, thanks to comments in the media from Industry Minister Tony Clement that the agency said there would be no difference in the data collected by a new survey.

To clear things up, a StatsCan staff townhall meeting was set for later that day, but abruptly called off. Hours later, Sheikh resigned.

The revelations come from almost 200 pages of emails and briefing notes released Tuesday in response to a request by the House of Commons industry committee.

They were provided by a government source.

Most of the documents were generated after the final decision was made, and some are blacked out, giving little insight into discussions between Statistics Canada and the government prior to the final decision.

Several are also undated or provided without context, making it difficult to ascertain where they fit in the decision process.

Liberal Industry critic Marc Garneau said it appears the Tories didn't put much thought into their decision on the census until after the fact.

"It's because of ideology. The Prime Minister or the prime minister's office said I think I'm going to make a change here . . . and to heck with science," he said in an interview.

The text of Sheikh's speech says the government's decision to change the census wasn't political interference with the respected agency.

It says politicians asked for options on conducting a voluntary survey, and "it was our duty as public servants to respond to this request."

After the change became public, the documents show StatsCan was bombarded with requests from Industry Minister Tony Clement's office and other Conservative MPs for more detailed information about new survey and how it would work.

In one exchange, the agency told Industry Canada that the response rate would be below 50 per cent before follow-ups, and there wasn't enough money for all the follow-up required.

At that time, the Privy Council Office — which serves the prime minister — was also telling the agency how to answer calls from the media, as well as trying to direct Sheikh's words.

In an exchange of e-mails on July 16, five days before Sheikh stepped down, he went back-and-forth with Industry Minister Tony Clement's office and the PCO over public remarks on the issue.

A senior PCO official asked Sheikh to include the phrase: "StatsCan is confident that the National Household survey will meet the needs of a broad range of users."

Sheikh countered with different wording: "a census by its design is able to meet a broader range of data demands than a survey. The National Household Survey will meet the needs of many users."

Later, Clement's office provided a version that deleted the phrase about census design.

The documents also show that StatsCan warned the Industry Department in March about the problems with voluntary surveys after Industry asked for information on the results of a test census carried out in 2009.

"On a voluntary census, we can get up to 65-70 per cent response rate, which is still not an acceptable outcome for a census," a StatsCan staffer wrote.

It would also require a substantial amount of additional funding, she wrote. The government is spending an extra $30 million to administer the voluntary household survey.

Sheikh resigned his post not because of the census switch, but because of the public suggestion by government officials that he was in agreement that the new data would be as good as that collected under the old mandatory system.

Tuesday's documents came the same day that Sheikh, who is now working at Queen's University, wrote an opinion editorial in The Globe and Mail. In it, he urges the government one last time to save the mandatory long-form.

Also Tuesday, Bloc Quebecois Leader Gilles Duceppe called on Prime Minister Stephen Harper to reconsider the change, suggesting a compromise that involves replacing jail sentences for those who ignore the survey with lesser penalties.

He said the government could simply withhold services — such as a passport or Employment Insurance — from people who fail to complete the census form.

But Harper made it clear Monday during a news conference in Vancouver that an 11th-hour reversal is not on his agenda.

The Federal Court is set to rule Wednesday on fast-tracking a bid by a Quebec group to stop the long-form census change.

The group Federation des communautes francophones et acadiennes du Canada argues the court needs to deal with their case before October. Otherwise, it says, the change could be unstoppable.