Suppression of data also occurs when certain census questions are not asked of all respondents. Persons living on Indian reserves and Indian settlements who were enumerated with the 2006 Census 2D questionnaire were not asked the questions on citizenship (Question 10), landed immigrant status (Question 11) and year of immigration (Question 12). However, it was possible that a census subdivision (CSD) or lower geographic area was enumerated using both the 2D questionnaire (for the on-reserve population) and the 2B questionnaire (for the off-reserve population). In this case, the following rules were used to determine if suppression had to be applied to all citizenship and immigration data for that CSD (or lower geographic area):
Consequently, citizenship, landed immigrant status and period of immigration data are suppressed for Indian reserves and Indian settlements at census subdivision and lower levels of geography where the majority of the population was enumerated with the 2D form. These data are, however, included in the totals for larger geographic areas, such as census divisions and provinces.
2D suppression is now an automated process for standard geographies within CAPSS, however, for custom geographies it is still a manual process. When using a custom geography it is the users' responsibility to ensure that, if required, all citizenship and immigration data are removed from their tabulations.
When creating a UDV that uses any immigration or citizenship variable, the same rules for 2D suppression apply.
In 2006, zeros were used to show where data were suppressed. In 2001, data were suppressed either by the removal of the geographic area from the table (e.g., in the 2001 topic-based tabulations) or by showing the data as 'null' (e.g., profile products displayed the 'null' data value for the area either as a '-', 'N' or as a 'D,' with the 'D' referring users to a special note).
For a complete list of Indian reserves and Indian settlements for which citizenship, landed immigrant status and period of immigration data are suppressed in 2006 and 2001, please refer to:
http://www12.statcan.ca/census-recensement/2006/ref/notes/sup_2D-eng.cfm