Census of Population

Detailed information for 2001

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

Data release - March 12, 2002 to May 13, 2003 (Major data releases)

• Questionnaire(s) and reporting guide(s)
• Description
• Data sources and methodology
• Data accuracy
• Documentation

Description

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.

Subjects

• 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 together with family members who live with them. Non-permanent residents are persons living in Canada who have a Minister's permit, a student or employment authorization, or who are claiming 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 Armed Forces stationed abroad, and all Canadian crew members of merchant vessels. Because persons outside the country are enumerated, the Census of Canada is considered a modified de jure census.

Sampling

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

Most of the long census questionnaires are distributed on a sample basis. The approach used to distribute these long questionnaires in sampling areas is a systematic 1 in 5 sample selection of households (i.e. every fifth household receives one). Within each collection unit (known as an enumeration area) there are, however, many reasons why there are not always four short questionnaires for each long questionnaire; for example, some households are unoccupied.

Initially, the weight for each sampled household in an enumeration area 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.

To ensure the best possible coverage, the country is divided into small geographic areas called enumeration areas (EAs). A census representative is responsible for at least one EA. The optimal number of dwellings in an EA ranges from 175 in rural areas to 650 in urban areas, an increase of 210 dwellings from the 1996 Census. In the 2001 Census, there were 42,851 enumeration areas in Canada, and 38,000 persons engaged in collecting the data.

(a) Self-enumeration
In the 2001 Census, approximately 98% of households were self-enumerated. For self-enumeration, a census representative drops off a questionnaire at each household during the two weeks before Census Day. An adult or responsible member of the household is asked to complete the questionnaire on Census Day for all members of the household, and then to mail the questionnaire in a pre-addressed envelope.

(b) Canvasser Enumeration
Approximately 2% of households were enumerated in the 2001 Census using the canvasser enumeration method. In this case a census representative visits the household and completes a questionnaire for the household by interview. This method is normally used in remote and northern areas of the country, and on most Indian reserves. The canvasser enumeration method is also used in certain urban areas where it is considered highly possible that respondents would be unlikely to return a questionnaire.

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

Error detection

This part of the census process involves the processing of all of the questionnaires completed by respondents, from the electronic capture of the information through to the creation of an accurate and complete retrieval database. The final database is transferred 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 2001 Census data products and services. A new objective for 2001 was to create an image retrieval system containing images (pictures) of all of the census questionnaires and Visitation Records so that subsequent processes requiring access to original census forms would not involve the handling of the thousands of boxes and paper documents.

There were five main Processing components for the 2001 Census:

· Regional Processing
· Imaging
· Interactive Verification
· Automated Coding
· Edit and Imputation

Regional Processing
Regional Processing is responsible for manually coding the industry and occupation responses and capturing the questionnaire information into a machine-readable format for subsequent processing system.

Imaging
In previous censuses, the remaining processing steps that required access to the questionnaires and Visitation Records used the paper versions of these documents. In 2001, for the first time, the need to handle the paper versions is eliminated by imaging (scanning) all of the questionnaires and Visitation Records as soon as they arrive at the 2001 Processing Site from the CCRA tax centres. Subsequent operations then have access to the questionnaire and Visitation Record images using an image retrieval system, rather than using the paper versions for their work.

Interactive Verification
The objective of the Interactive Verification operation is to produce a "cleaner" version of the raw census data by applying some basic edits. This allows subsequent operations to further process the data using automated systems, without having to refer to the original documents or their images.

Automated Coding
Automated Coding matches the write-in responses that are data-captured from the long questionnaires during Regional Processing against an automated reference file/classification structure containing a series of words or phrases and corresponding numerical codes.

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

An assessment of the quality, comparability and limitations of the 2001 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 data quality evaluation studies are directed beyond the immediate certification objectives. The studies provide indications of the quality of the census data from the source of error--coverage, response, non-response, processing and sampling--and of the impact on individual variables. The result of these studies, along with the certification analysis, will be integrated into a series of technical reports. The basic unit used in the calculation of the response rate is the household. (This includes private and collective households, households outside Canada, random additions for households misclassified as vacant and total non-response [Form 4] households. It excludes unoccupied dwellings and dwellings occupied only by foreign or temporary residents.) In the 2001 Census, there were 11,590,763 in-scope households on the database, of which 185,121 were total non-response (Form 4) households. There were 11,405,642 households with at least some data. The overall response rate was therefore 11,405,642 / 11,590,763 = 98.40%.

Documentation

• Census Web Site
  - For all census documentation, please refer to the following address: http://www12.statcan.gc.ca/census-recensement/index-eng.cfm
  • Format: Census Web Site - HTML[HTML]