麻豆传媒

 

Don't mess with the census

- August 5, 2010

statscan
Statistics Canada offices.

Perhaps the only positive to come out of this summer鈥檚 brouhaha over the federal government鈥檚 decision to replace the mandatory long-form census with a voluntary survey is the rebranding of the Canadian statistician.聽

For fair play and honesty, StatsCan is the new Mountie.

鈥淚t鈥檚 absolutely bizarre,鈥 says 麻豆传媒 professor emeritus of statistics Chris Field, sporting a bemused grin, 鈥淭o see statistics on the front page of the Globe for聽10 days or two weeks in a row is unprecedented.鈥

While Munir Sheikh reaching near-heroic status may be good for the profession鈥檚 profile, the point is largely moot to Professor Field. What confounds him is the government鈥檚 decision to interfere with census methodology in the first place.

鈥淚 don鈥檛 understand the government鈥檚 motives,鈥 he says plainly. 鈥淗istorically, they have left the methodological issues -- how the surveys are collected, all the issues of analyzing the data -- to the professionals. And here, they are simply ignoring professional advice.鈥

Dr. Field started teaching statistics at 麻豆传媒 in 1970. He was the President of the Statistical Society of Canada and a former member of the methodology advisory committee for Statistics Canada.

The first national census was held in 1861. Here, a census taker interviews a farmer in the 1930s.

Aside from a close call in 1986, when Brian Mulroney鈥檚 government nearly cut a census to save money, he cannot recall any government action of the last 40 years that would affect the census as fundamentally as this current decision regarding the long form.

What happens when a census stops being mandatory and becomes voluntary? The simple answer is, lots. It stops being a census and that change starts to unravel our statistical knowledge of Canada, says the group of Dal social scientists discussing the issue in sociology Professor Yoko Yoshida鈥檚 office.

鈥淲hen we teach statistics in our undergraduate courses,鈥 says Howard Ramos, associate professor of sociology, 鈥渙ne of the first lessons that are taught is that you have to get a representative non-biased sample.鈥

鈥淲henever you move to doing a voluntary census,鈥 Prof. Ramos explains, 鈥渋t moves from being a census to a survey and you no longer have the representation of the full population and you end up having systematic bias that creeps into it.鈥

A mandatory census gives statistical results professionals call gold standard data.

鈥淭he information that stems from the census is very accurate,鈥 says Prof. Yoshida, for two reasons: the high response rate and because the responses draw information from one-fifth of the population across all parts of the country.

As the gold standard, census data gets applied to research all across the country.

鈥淢any voluntary surveys use the census to gold standard their biases, to understand what they missed and make corrections for that,鈥 Prof. Field explains. 鈥淲ithout that gold standard of a reliable database that can be trusted, we simply have no idea. The census data -- I won鈥檛 say becomes useless -- but has much less use than it currently has.鈥

'Rupture in research'

There will be a catch-22 when it comes to verifying the voluntary census itself, says Martha Radice, professor of social anthropology. 鈥淭he catch-22,鈥 she says 鈥渋s that we won鈥檛 even be able to verify how representative the new voluntary national household survey [the replacement for the long form] is, because we鈥檒l have lost that baseline benchmark data.鈥

鈥淭here will be a rupture in research in Canada,鈥 Prof. Radice adds, 鈥渨hereby after 2011, we lose all comparability with past data on basic things like how do you get to work, where do you work, does anyone living at this address have reduced mobility,鈥 and other questions on the long form.

鈥淲ithout having accurate data on this kind of basic information,鈥 says Prof. Ramos, 鈥渨e literally could be building roads in the wrong places.鈥

Changing the census has implications for Atlantic Canada, says Prof. Ramos who studies immigration patterns across the Atlantic provinces with Dr. Yoshida.

鈥淲e have a small population and we are often missed in the national surveys,鈥 says Prof. Ramos. 鈥淭he census is one of the only means in which we can get quality data on Atlantic Canada. The migration question on the census is one of the main tools to understand who is coming in and out of the province. If this is not going to be part of the long form, we鈥檙e going to have more inaccurate means to understand who is coming in and out and why they are coming in and out.鈥

Ninety-five per cent of Canadians currently respond to the census. "A voluntary census runs a high risk of generating low response rate from 聽socially and economically marginalized groups," Yoshida says. Their non-response will skew results across the country.

Compounded the problem

Even if the government spends $25 million to promote census participation, Prof. Field does not feel that response can be matched by voluntary means.

鈥淯nfortunately, by all the publicity, if it does remain voluntary, the non-response rate, in spite of all the advertising, is still going to be between and 10 and 20 per cent,鈥 Professor Field says.

鈥淭he government tells people they should be worried about their privacy, and a lot of people are going to see that long form and say, 鈥淚鈥檝e listened to the government and I am not going to fill it out.鈥 They鈥檝e compounded the problem.鈥

Back in 鈥86, statisticians managed to convince the Mulroney government to abandon its plans 鈥渜uietly,鈥 says Prof. Field. He calls current proposal by the 鈥渧ery sensible. It gave the government a nice compromise to get out of this situation, to keep it [mandatory] for this census.鈥

It鈥檚 with the same quiet sensibility that Prof. Field hopes a compromise can be reached before the next census in 2011.


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