Census of Population

Detailed information for 2006




Every 5 years

Record number:


The census is designed to provide information about people and housing units in Canada by their demographic, social and economic characteristics.

Data release - March 13, 2007 to May 1, 2008 (Major releases, please refer to left sidebar, under the heading "The Daily")


Statistics Canada conducts the Census of Population in order to develop a statistical portrait of Canada and Canadians on one specific day. The census is designed to provide information about people and housing units in Canada by their demographic, social and economic characteristics.

The Census of Population is a reliable basis for the estimation of the population of the provinces, territories and local municipal areas. The information collected is related to more than 80 federal and provincial legislative measures and provides a basis for the distribution of federal transfer payments. The census also provides information about the characteristics of the population and its housing within small geographic areas and for small population groups to support planning, administration, policy development and evaluation activities of governments at all levels, as well as data users in the private sector.

Clients: Federal government, provincial and territorial governments, municipal governments; libraries; educational institutions; researchers and academics; private industry; business associations labour organisations; ethnic and cultural groups; private citizens; public interest groups.


  • Commuting to work
  • Education, training and learning
  • Employment and unemployment
  • Families, households and housing
  • Globalization and the labour market
  • Immigration and ethnocultural diversity (formerly Ethnic diversity and immigration)
  • Income, pensions, spending and wealth
  • Indigenous peoples (formerly Aboriginal peoples)
  • Industries
  • Labour
  • Languages
  • Occupations
  • Population and demography
  • Population estimates and projections
  • Unpaid work

Data sources and methodology

Target population

The census enumerates the entire Canadian population, which consists of Canadian citizens (by birth and by naturalization), landed immigrants and non-permanent residents and their families living with them in Canada. Non-permanent residents are persons who hold a work or student permit, or who claim refugee status.

The census also counts Canadian citizens and landed immigrants who are temporarily outside the country on Census Day. This includes federal and provincial government employees working outside Canada, Canadian embassy staff posted to other countries, members of the Canadian Forces stationed abroad, all Canadian crew members of merchant vessels and their families. Because people outside the country are enumerated, the Census of Canada is considered a modified de jure census.

Instrument design

The content determination process is required for every census and consists of the following steps:

The consultation process is the first step in determining the content of the census. By assessing users' socio-economic data needs, an evaluation can be made regarding the best way to meet those needs-either through a content change to the census or through other Statistics Canada data sources.

Data needs expressed during the consultation process are closely examined in light of the above-mentioned criteria. Whenever a modification to census content is considered, the changes need to be carefully tested before they can be implemented.

As part of the content determination process, Statistics Canada undertakes an extensive content testing program. Qualitative testing (focus groups and in-depth one-on-one interviews) as well as large sample quantitative tests are methods used to determine the quality of information that would result from changes made to the questions and questionnaire design.

Before each census, the options developed by Statistics Canada for the content of the census are reviewed by Cabinet. Following this and in accordance with the Statistics Act, the questions for the census are prescribed by the Governor in Council through an Order in Council which is published with the schedule of questions in the Canada Gazette, Part I. The Order in Council also includes a recommendation asking the Governor General in Council to choose the month of the census.

For a more complete description of the census consultation process follow the link below.


This survey is a census with a cross-sectional design.

Questions on age, sex, marital status, mother tongue and relationship to Person 1 are asked of 100% of the population. However, the bulk of census information is acquired on a 20% sample basis using the additional questions on the long form questionnaire (2B). The approach used to distribute these long forms in sampling areas is a systematic 1 in 5 sample selection of dwelling (i.e. every fifth dwelling receives one). Within each collection unit (formerly known as an enumeration area) there are, however, many reasons why we do not end up receiving exactly 4 short forms for each long form. For example, some dwellings are unoccupied.

Initially, the weight for each sampled household in a collection unit is simply the ratio between the total number of households and the number of sampled households. However, with this initial weight, we cannot be certain that all sub-groups (such as adult males) will be properly represented with the sample. To ensure that the most important sub-groups are consistently estimated, a regression estimation weighting procedure is used. This method constrains the sample weights to known population counts for the most important sub-groups for both the dissemination unit (known as the dissemination area) and for a larger geographic unit (known as the weighting area). The estimation method will adjust the initial household weight as little as possible to produce fully representative estimates from the sample data.

Data sources

Responding to this survey is mandatory.

Data are collected directly from survey respondents.

This stage of the process aims at making sure that Canada's 12.7 million households, about 32.5 million persons, are enumerated. The activities and rules governing its execution can be grouped under the following headings:

· Block canvassing to validate address listings
· Census questionnaires delivery methods
· Questionnaires completion methods
· Collective dwellings - Enumeration and collection methods

For a description of the census delivery preparation and methods follow the "Additional documentation (in PDF format)" link below.

View the Questionnaire(s) and reporting guide(s).

Error detection

Census data processing:

This part of the census activities involves the processing of all of the respondent completed questionnaires, from the data capture of the information from the paper questionnaires and the integration of the data collected electronically, through to creating an accurate and complete database. The final database is made available to the Data quality measurement project to determine the overall quality of the data, and to the Dissemination project for the production and marketing of the 2006 Census data products and services.

Processing of the census responses is divided into five main activities:

· Receipt and registration (follow "Additional documentation" link below)
· Imaging and data capture from paper questionnaires (follow link below)
· Edits and failed edit follow-up (follow link below)
· Automated coding (follow link below)
· Edit and imputation (see Imputation)
· Weighting (see Estimation)


Edit and imputation:

The data collected in any survey or census contains omissions or inconsistencies. These errors can be the result of respondents missing a question, or they can be due to errors generated during processing. For example, a respondent may be unwilling to answer a question, may fail to remember the right answer, or may misunderstand the question. Census staff may code responses incorrectly or may make other mistakes during processing.

After the capture, completeness and coverage editing and corrections, and coding operations are complete, the data are processed through the final edit and imputation activity which is mostly fully automated. The editing process detects the errors, and the imputation process corrects them.

A series of detailed edit rules that identify any missing or inconsistent responses are applied. These missing or inconsistent responses are corrected most of the time by changing the values of as few variables as possible through imputation. Imputation invokes "deterministic" and/or "minimum change hot deck" methods. For deterministic imputation, errors are corrected by inferring the appropriate response value from responses to other questions. For minimum change hot deck imputation, a record with a number of characteristics in common with the record in error is selected. Data from this "donor" record are borrowed and used to change the minimum number of variables necessary to resolve all the edit failures.

The Nearest-Neighbour Imputation Methodology (NIM), developed for the 1996 Census to perform the edit and imputation for basic demographic characteristics such as age, sex, marital status, common law and relationship to Person 1, was expanded and implemented into a new generic system for the 2001 Census called CANadian Census Edit and Imputation System (CANCEIS), which is a PC-server-oriented system as opposed to the main frame, to process demographic (age, sex, marital status, common law and relationship to Person 1), mobility, labour, place of work, and mode of transportation variables.

The 2006 Census saw a further extension of CANCEIS to all of the remaining variables. This continued to allow more extensive and exact edits to be applied to the response data while preserving responses through the minimum change hot deck imputation.



Questions on age, sex, marital status, mother tongue and relationship to Person 1 are asked of 100% of the population. However, the bulk of census information is acquired on a 20% sample basis using the additional questions on the long form questionnaire. "Weighting" is used to project the information gathered from the 20% sample to the entire population.

The weighting method provides 100% representative estimates for the 20% data and maximizes the quality of sample estimates.

For the 2006 Census, weighting will employ the same methodology used in the 2001 Census known as calibration estimation. This begins with initial weights of approximately 5 and then adjusts them by the smallest possible amount needed to ensure closer agreements between the sample estimates (e.g., number of males, number of people aged 15 to 19, etc.) and the population counts for age, sex, marital status, common-law status and household.

This is the last processing step in producing the final 2006 Census databases, the source of data for all publications, tabulations and custom products.

Quality evaluation

Throughout the census-taking process, every effort was made to ensure that the results would be of superior quality. The data quality measurement stage is intended to determine the overall quality of the census data. While rigorous quality standards are set for collecting and processing the data, and activities such as the communications program helped reduce non-response, it is impossible to eliminate all errors. Consequently, the quality of the data is measured in order to provide users with information about the reliability of the data and to improve data quality in future censuses.

Disclosure control

Statistics Canada is prohibited by law from releasing any data which would divulge information obtained under the Statistics Act that relates to any identifiable person, business or organization without the prior knowledge or the consent in writing of that person, business or organization. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.

In all products released, procedures are applied to prevent the possibility of associating statistical data with any identifiable individual: the data are randomly rounded and they are suppressed for certain geographic areas. Random rounding is a method whereby all figures in a tabulation, including totals are randomly rounded (either up or down) to a multiple of "5", and in some cases "10". This technique provides strong protection against direct, residual or negative disclosure, without adding significant error to the census data. However, figures on population counts only are not rounded since they provide no information on the characteristics of these populations.

Area suppression results in the deletion of all characteristic data for geographic areas with populations below a specified size. All data for standard and non-standard geographic areas with a total population of less than 40 persons are suppressed. If the data contain an income distribution, those areas with a population below 250 persons are suppressed. For postal code geography, the three-character forward sortation areas will be suppressed using the 40-person rule. For the six-character local delivery units, a 100-person suppression rule will be used. In all cases, suppressed data are included in the appropriate higher aggregate subtotals and totals.

Revisions and seasonal adjustment

This methodology does not apply to this survey.

Data accuracy

While several factors such as those noted under the heading Error Detection can influence census data accuracy, the accuracy of census counts and data is first affected by the degree to which the total population is missed in the census (undercoverage). The census count of 31,612,897 persons in 12,506,814 dwellings does not include persons living in dwellings missed during census enumeration, or persons mistakenly omitted from the questionnaires of responding dwellings. (The count of dwellings includes occupied private and collective dwellings and responses received from outside Canada. It excludes unoccupied dwellings and dwellings occupied only by foreign and temporary residents.) Nationally, the final estimate of the 2006 Census net undercoverage rate is 2.8%, compared with 3.1% for the 2001 Census. Net census undercoverage varies from one province and territory to another and from one age group to another.

The quality of the census count is further impacted by response to the census. The majority of the above count consists of 30,679,721 persons enumerated in 12,071,390 responding dwellings. The remainder of the census count was estimated on the basis of a sample survey of known dwellings that did not return a census questionnaire and consists of 933,176 persons imputed into 435,424 dwellings. The overall response rate can be calculated as 12,071,390/12,506,814, equaling 96.5%. While this is slightly lower than in the 2001 Census, the methodology underlying this last adjustment differs from that used in 2001 with the result that response rates for the 2001 and 2006 censuses are not strictly comparable.

An assessment of the quality, comparability and limitations of the 2006 Census data is carried out as an integral part of release and dissemination activities. All variables are certified before release, by way of a set of brief studies designed to judge the consistency of the data with that of previous censuses and that of alternate data sources. This process is augmented by measures of data quality provided by evaluation studies. The studies provide indications of the quality of the census data as affected by potential sources of error--e.g., coverage, response, non-response, processing and sampling--and of the impact on individual variables.


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