Stephen Gordon points to four essays on the census from the current issue of Canadian Public Policy. Separately, he himself takes on the idea that a voluntary census will provide more truthful responses.
It is possible that individual files will have fewer errors if the census is voluntary, but these gains look to be small and – in the absence of empirical evidence – mainly hypothetical. In contrast, the losses associated with self-selection bias are large and well-documented. If the government wishes to pursue this idea, then it should be field-tested before making it a basis for policy.
But the main reason why I am skeptical of claims that a voluntary survey will yield more ‘honest’ results is the way the government has handled the file. After a summer of mockery and dismissiveness, the government and its supporters have created a significant constituency that now believes that the census is a tool of its political opponents. We’re going to get the worst of both worlds: a census with a biased sample and a higher rate of inaccurate responses.