If Statistics Canada was surprised by the Conservatives before the last census, this time it was ready for the unexpected.

Stephen Harper's government revealed it would kill the mandatory long-form questionnaire less than a year before the 2011 census was mailed out and two years after an election campaign where the topic never came up. The statistics agency scrambled to get a voluntary National Household Survey in place.

When the Liberals were sworn into office in November, one of their first orders of business was to announce the reinstatement of the long-form census.

The timeline seemed very tight — the first forms are to go out to residents in the North in February.

But Marc Hamel, the census program director general, says the agency had planned for risks associated with the 2016 census. One of those risks was if a new government decided to bring back the long questionnaire.

"It had already been in the public sphere that opposition parties last year were saying, if they were elected, they would bring back the mandatory long-form census, so we had started to look at how that would be possible," Hamel said in an interview.

What do we use the census information for, why is it important for communities, and why is it important for people to participate? - Marc Hamel, Statistics Canada census program director general

The agency decided to design the questionnaire in a more adaptable format.

Rather than sending selected households separate pieces of mail with the short form and then the National Household Survey, the questionnaires were integrated into one document.

"That design was going to be efficient and it was going to work for both approaches," said Hamel. "From that perspective, no redesign was required. We were simply able to move ahead with the same questionnaires that we had already designed for 2016."

Also, because most Canadians fill out the census online — 54 per cent in 2011 — changing details in a computer system was not a major overhaul.

The letter that accompanies the questionnaires will allow the agency to underline that the long part is mandatory again. Census staff will also drive home the message.

One in four to fill out mandatory census

Fewer people will have to fill out the long form than last time, one in four households rather than one in three with the NHS. Statistics Canada has had to print more short-form questionnaires as a result of the change.

The agency doesn't think it will save money with fewer people getting the bigger package. It expects it will have more responses to process because of the return to the mandatory format.

The main challenge will come from adjusting to the data logistics of bringing back the long-form census. Bar codes help the agency keep track of where they drop off which forms and some of that work will have to be rejigged.

StatsCan to launch census campaign

There will also be a public awareness campaign to make sure that people realize they need to fill out the forms. Hamel says the agency never really emphasizes the penalties associated with not filling out the forms — a $500 fine or up to three months in jail, or both.

"Census information is really important, and that's where we put the focus," said Hamel. "What do we use the census information for, why is it important for communities, and why is it important for people to participate?"

Census day is May 10, and most people will begin receiving letters and packages on May 2.

Statistics Canada is also busy looking for about 35,000 workers to help with the census. Details are on its website at www.census.gc.ca.