OTTAWA - Statistics Canada is asking Canadians to provide their social insurance numbers during test runs for the 2016 census, part of an effort to make the survey data more reliable.

The Conservative government eliminated the mandatory long-form census in 2011, saying it was too intrusive and replacing it with the voluntary National Household Survey.

Information on thousands of smaller Canadian communities was subsequently not released because of weak response rates.

The agency is now asking a sample of Canadians who fill out tests of the mandatory short-form census to include their social insurance numbers, which connect to specific information at the Canada Revenue Agency.

That data will allow Statistics Canada to draw a picture of certain types of households, and help it fill in the blanks when certain households choose not to complete their different surveys.

If the test works, the agency might be able to one day replace an entire section of questions on income in the long-form survey by just asking for the number.