Sunday, August 15, 2010

Canadian census long form

The conservative government in Canada is seeking to eliminate the Census "long form" (or, more gently, to make it voluntary). The US did this a few years ago but replaced the long form with the (still mandatory) American Community Survey, so that the issue of having data (almost) uncontaminated by non-random response bias, which to me is the key issue in the debate over the long form, does not arise. The Canadians propose to make the long form voluntary, thus corrupting all the estimates it generates with selection bias.

Here is a fairly reasonable Globe and Mail editorial and here is a somewhat over-heated and remarkably political editorial from Nature.

Here are some tweets from a Canadian government minister who does not, as the saying goes, get it.

Shame on the conservatives in Canada for not being serious on this one. They are an embarrassment to themselves and to Canada and are sending a strong signal that they are not serious about good government. And that matters in Canada, where the analogue to "life, liberty and the pursuit of happiness" is "peace, order and good government."

My pals at Reason also do not distinguish themselves on this one. The fact that the data are not perfect is an argument for improving the data, not abandoning the attempt. More broadly, it seems to me that classical liberals should support govenrment production of public goods, like knowledge, and the evidence-based policy making it supports, particularly given, at least in my experience, that most programs and policies cannot pass a cost-benefit test when rigorous evidence is available.

Regular readers may object that I cannot complain about mandatory jury duty and then not complain about a mandatory census, but the census from mandatory jury duty in three important ways. First, the tax is small. Completing the Census for takes a few minutes. Second, the tax is uniform. Everyone pays the same small tax, rather than jurors who get stuck on long trials paying a gigantic in-kind tax and jurors who escape without being assigned to a trial paying no tax. Third, volunteer jurors are probably a good substitute (perhaps even a superior substitute) for mandatory ones, while voluntary surveys are not a good substitute for mandatory ones, particularly not at the key task of establishing solid benchmark statistics against which all the other voluntary surveys can be judged.

I do think that the Census should aim to minimize the burden of the long form. 20 percent of the population may be much more than is required to get very precise population estimates, even at a provincial or metropolitan area level. In a sense, reducing the population subject to the requirement to complete the long form is what the US did by replacing it by the ACS.

More broadly, given Facebook and Google and all the rest, it seems a bit bizarre for people to worry about the privacy implications of the innocuous questions on the long form.

Hat tip on the tweets to a friend at a government contractor in Canada.


Dan said...

In what sense does requiring people to fill out a survey eliminate non-response bias?

If you wanted to refuse the survey because you were concerned about your privacy, I imagine mandated response would induce you to answer randomly, or at least uninformatively. As a census user, I certainly prefer that the long form be mandatory (or I guess that the ACS be mandatory), and my prior is that, conditional on being forced to fill out a survey, people are truthful, even if they'd rather not reveal information. But I'm not sure why this is true.

taylorhui said...

Dan, providing inaccurate answers to a census is the same offense as refusing answers under the Statistics Act 23(2).

"23(2) Subject to section 8, a person to whom a form is sent pursuant to subsection (1) shall answer the inquiries thereon and return the form and answers to Statistics Canada properly certified as accurate, not later than the time prescribed therefor by the Minister and indicated on the form or not later than such extended time as may be allowed in the discretion of the Minister. 1970-71-72, c. 15, s. 22; 1980-81-82-83, c. 47, s. 41."