Data quality and confidentiality

• Incompletely enumerated Indian reserves and Indian settlements
• Adjustment of population counts
• Detailed explanation: Differences between Statistics Canada's census counts and population estimates

Incompletely enumerated Indian reserves and Indian settlements

In 2011, there were a total of 31 Indian reserves and Indian settlements that were 'incompletely enumerated.' For these reserves or settlements, enumeration was either not permitted or was interrupted before it could be completed, or enumeration was not possible because of natural events (specifically forest fires in Northern Ontario).

Compared to previous censuses, there was a decrease in the number of band councils that did not give permission to enter their territory to conduct the census, from 18 Indian reserves and Indian settlements in 2006 to 14 in 2011.

There were 13 Indian reserves and Indian settlements where enumeration was not possible as a result of forest fires in Northern Ontario at the time of census collection. Collection for these communities was done at a later time. While the data are not included in the 2011 Census tabulations, it is expected that separate special tables showing data for these communities will be made available at a later date, subject to data quality evaluation.

The 2011 Census population and dwelling counts are not available for the 31 incompletely enumerated Indian reserves and Indian settlements, and are not included in 2011 Census tabulations. Data for geographic areas containing one or more of these reserves and settlements are noted accordingly. Because of the missing data, users are cautioned that for the affected geographic areas, comparisons (e.g., percentage change) between 2006 and 2011 are not precise. The impact of the missing data for higher-level geographic areas (Canada, provinces and territories, census metropolitan areas and census agglomerations) is very small. However, the impact can be significant for smaller areas, where the incompletely enumerated Indian reserves and Indian settlements account for a higher proportion of the population.

Appendix 1 provides the list of incompletely enumerated Indian reserves and Indian settlements for the 2011 Census, along with population counts from the last two censuses (where available).

Appendix 2 shows the list of incompletely enumerated Indian reserves and Indian settlements for the 2011 Census by province, census division and, where applicable, for the census metropolitan area or census agglomeration.

Adjustment of population counts

Statistics Canada is committed to protect the privacy of all Canadians and the confidentiality of the data they provide to us. As part of this commitment, some population counts of geographic areas are adjusted in order to ensure confidentiality.

Counts of the total population are rounded to a base of 5 for any dissemination block having a population of less than 15. Population counts for all standard geographic areas above the dissemination block level are derived by summing the adjusted dissemination block counts. The adjustment of dissemination block counts is controlled to ensure that the population counts for dissemination areas will always be within 5 of the actual values. The adjustment has no impact on the population counts of census divisions and large census subdivisions. Population counts of federal electoral districts will be within 7 of the actual values. Dwelling counts are unadjusted.

Detailed explanation: Differences between Statistics Canada's census counts and population estimates

The 2011 Census counted 33,476,688 people in Canada during the national enumeration with reference day May 10, 2011. This count is lower than the published July 1, 2011 population estimate of 34,482,779 people. The difference between the two figures is not unexpected and is similar to that which was experienced in the 2006 Census. This note outlines why there are differences between census counts and population estimates.

The objective of a census is to provide detailed information on the population at a single point in time. In this respect, one of its goals is to enumerate the entire population. Inevitably, however, some people are not counted, either because their household did not receive a census questionnaire (for example, if a structurally separate dwelling is not easily identifiable) or because they were not included in the questionnaire completed for the household (for example, the omission of a boarder or a lodger). Some people may also be missed because they have no usual residence and did not spend census night in any dwelling. In contrast, a small number of people may also be counted more than once (for example, students living away from home may have been enumerated by their parents and by themselves at their student address).

To determine how many individuals were missed or counted more than once, Statistics Canada conducts postcensal coverage studies of a representative sample of individuals. Results of these studies in combination with the census counts are used to produce current population estimates which take into account net undercoverage.

Postcensal coverage study results are usually available two years after enumeration date. For the 2006 Census, preliminary postcensal study results were released in March 2008. Final estimates of coverage error were subsequently released in September 2008.

For the 2011 Census, preliminary coverage study will be released in March 2013 and the results of the final study will be released in September 2013. These will in turn be used to revise and update the population estimates based on the 2011 Census results. Consequently, a series of revised population estimates for the period 2006 to 2013 will be disseminated in September 2013.

One of the advantages of the census is to provide counts for small regions (below the census division level) for which demographic estimates are not available or are less precise. On the other hand, population estimates provide a more accurate measure of population counts. In addition, estimates are utilized to measure the evolution of the population between censuses and provide explanations behind the population growth. They are available on a quarterly and annual basis at the national, provincial and territorial levels and are also available at the subprovincial level on an annual basis.