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Taking a Census of Population


The dissemination of census results is the culmination of a multi-stage process that begins long before Census Day. The census is a unique undertaking on a vast scale, and it has its own special challenges. Collecting information from some 31.6 million people and more than 13.5 milllion dwellings is a daunting challenge. Although censuses are conducted only once every five years in Canada, the census cycle extends over a number of years, as figure B shows.

Figure B
2006 Census timeframe
Task title Timeframe1
1. This timetable is only showing time of intense activities of each task.
Content determination April 2002 to August 2005
Questionnaire production May 2005 to August 2005
Data collection February 2006 to August 2006
Data processing April 2006 to December 2006
Edit and imputation July 2006 to December 2007
Coverage measurement studies July 2006 to September 2008
Dissemination March 2007 to May 2008

Before each census, Statistics Canada consults data users and interested parties across Canada for their views on the type and extent of information that should be available through the census database. The goal of these consultations is to ensure that Statistics Canada takes account of emerging social and economic issues and, where appropriate, uses the census and post-censal surveys to shed light on them. In addition to the consultation process, the census questions undergo an extensive testing process.

Content determination

For the 2006 Census, Statistics Canada implemented an integrated approach to user consultation. For the first time, census consultations with data users combined discussions on content determination, geography and the dissemination program.

As well, due to the limited content change possibilities, other socio-economic data sources available at Statistics Canada were presented to data users as alternatives to fulfill their emerging data needs. Statistics Canada's extensive socio-economic statistical program includes a variety of complementary data sources which address three major types of data needs in ways that the census cannot:

  • a need for current data on a regular basis
  • a need for information which includes complex or sensitive questions which are best administered by an interviewer
  • a need for information to determine the underlying causes of a phenomenon, requiring a set of data that extends over longer periods of time.

Data needs were evaluated in light of a number of considerations including the respondent's right to privacy, legislative requirements, availability of other sources to meet data needs, respondent burden, and collection and processing costs.

A group of people stands above a large Canadian flag.

2006 Census consultation

In preparation for the 2006 Census, Statistics Canada continued its tradition of consulting data users and other interested persons to obtain their views on the content of the next census questionnaire. Participation included representatives from public libraries, academia, local governments, federal, provincial and territorial government departments, private sector, the general public, special interest groups and licensed distributors of Statistics Canada data.

Statistics Canada has always recognized the importance of consultation and, for this census, emphasized the need for continuous dialogue with its data users. Consequently, several rounds of integrated consultation were held for the 2006 Census, not only to collect feedback, but also to keep data users informed of the status of census plans and decisions.

The first round of consultation was initiated in 2002 and focused primarily on the content of the census questionnaire. In 2003, a follow-up consultation on the newly proposed education module content was conducted. The 2004 round of consultation focused primarily on accumulating feedback on the dissemination program and the proposed directions for 2006 geography as well as providing data users with an update of the qualitative testing for the questionnaire content. In 2005, sessions were held with data users to inform them of the results of the 2004 Census Test, the final content of the census questionnaire, the directions of the dissemination program and the proposed geography product line. Input on the census product line was gathered during the 2006 round of consultation.

One of the primary vehicles used to solicit user input for the 2006 Census was the consultation guide. In fact, one guide was produced to solicit feedback on the content of the questionnaire and another on the dissemination program/proposed directions for 2006 geography. An Internet site was also constructed to give access to the consultation material and offered a quick and easy way to submit input. As well, to ensure follow-up on the comments received, consultation reports were produced and sent to participants.

All reports were published as official Statistics Canada publications and were made available, free of charge, through the online catalogue and on the 2006 Census consultation website.

In total, the consultation period included more than 100 meetings across the country and 2,647 comments on census subjects were captured.

Number of comments received by census category
Census category Number of the comments received % of the comments submitted
Collection/Field operations 98 4
Content 750 28
Dissemination 1,239 47
Geography 330 12
General 230 9
Total 2,647 100

Very few major emerging data needs were expressed with regards to the 2006 Census content. In fact, the comments submitted during the multiple rounds of consultation were well distributed across the various census topics as shown in the above table. Ensuring that the 2006 Census content remain as similar as possible to the 2001 Census content was identified as the top priority by consultation participants.

Consultation feedback

The feedback collected through consultation was carefully analysed against several criteria. With respect to census content, once the analysis was completed, new questions—which take into account suggested adjustments and new needs—were tested through the content-testing program. (More detailed information is available in the 2006 Census Content Consultation Report.)

Content testing

Qualitative testing

Before adding new questions to the census or modifying the existing ones, changes are tested by small groups of individuals and are then evaluated quantitatively. Discussion groups and one-on-one interviews are organised in order to examine which way the respondents interpret the questions and the instructions that are provided.

From September 2002 to November 2003, five qualitative tests took place in order to determine the content of the questionnaire for the 2004 Census Test. Each test involved an average of 100 participants. During this period, more than 200 versions of questions and/or instructions were tested and of this number, 32 content changes were retained for the 2004 Quantitative Census Test. Rounds of qualitative testing produced new content concepts as well as a new format for the questionnaire.

More information is available online in the Overview of the 2004 Census Test, as well as the Summary of Content Analysis Results - 2004 Census Test, released in March 2006.

Statistical test

Two quantitative tests were used to evaluate the new format, the new questions, and the changes that should be made to the existing questions. Follow-up interviews were also conducted with the respondents in order to identify any problem or difficulty related to the use of the electronic questionnaire available on the Internet.

Census Test

The Census Test was conducted on May 11, 2004 in 300,000 households in the Atlantic, Quebec and Prairie regions. These regions were chosen in order to produce a sample which represented francophone and anglophone households, as well as a mix of geographic regions, e.g. cities, villages and agricultural areas. Participation in the test was voluntary.

Red tulips highlight the Peace Tower.

Approval of the 2006 Census questions

Statistics Canada used the results of the 2004 Census Test, together with the results of qualitative testing, recommendations from major data users and national and community organizations, as well as letters from private citizens to develop options for consideration and decision by Cabinet. Following approval by Cabinet and the prescription of the questions by the Governor in Council, the questions were published in the Canada Gazette Part 1 in April 2005. The 2006 Census questions are available on the Statistics Canada website on the Census of Population page.

Questionnaire production

Questionnaire design is important for several reasons. It reflects on Statistics Canada's public image, can affect the quality of the data obtained, and can also be a factor in the efficient collection and processing of data. Designing a user-friendly questionnaire that satisfies the requirements of collection, processing, and communications is a challenge. Space on the questionnaire is restricted, thereby limiting the number and length of questions that can be asked. Instructions and examples must also be included on the questionnaire.

Once design has been finalized, questionnaires must be typeset and edited, printing and packaging contracts arranged, quality control measures carried out, and delivery of more than 100,000 documents monitored. The following is a short list of the many types of questionnaires, booklets, envelopes and related items produced:

Form 2A
is the short Population Questionnaire. It is used to enumerate all usual residents of 4/5 of all private dwellings.

Form 2B
is the long Population Questionnaire. It is used to enumerate 1/5 of all usual residents of all private dwellings. It is also used to enumerate residents of a Hutterite colony in these areas.

Form 2C
is used to enumerate people posted outside Canada, including Canadian government employees (federal and provincial) and their families, and members of the Canadian Forces and their families. It is also used to enumerate all other Canadian citizens and landed immigrants and non-permanent residents outside Canada who wish to be enumerated.

Form 2D
is the Northern and Reserves Questionnaire. It is used to enumerate northern areas and most Indian reserves, Indian settlements, Indian government districts and terres réservées. In canvasser areas, it is also used to enumerate usual residents of a Hutterite colony.

Form 3A
is the Short Individual Census Questionnaire. It is used in private dwellings enumerated on Form 2A, to enumerate usual residents who wish to be enumerated in private dwellings (e.g., roomers, lodgers, boarders). It is also used in collective dwellings enumerated from administrative records, to enumerate usual residents and live-in staff members.

Form 3B
is the Long Individual Census Questionnaire. It is used in private dwellings enumerated on Form 2B, to enumerate usual residents who wish to be enumerated in private (e.g., roomers, lodgers, boarders). It is also used in self-enumeration collective dwellings (except Hutterite colonies), to enumerate usual residents and live-in staff members.

The census questionnaires were produced in both official languages, in both regular and large print1 . The census questions were translated into 62 non-official languages, including Aboriginal languages, and were also available in Braille and on audio cassette.

Data collection

This stage of the census process ensured that each of the 13.5 million dwellings in Canada received a census questionnaire.  The census enumerated the entire population of Canada, which consists of Canadian citizens (by birth and by naturalization), landed immigrants, and non-permanent residents together with family members living with them. Non-permanent residents are persons living in Canada who have a Work or Study Permit, or who are claiming refugee status, and family members living with them.

The census also counted Canadian citizens and landed immigrants who were temporarily outside the country on Census Day. This included federal and provincial government employees working outside Canada, Canadian embassy staff posted to other countries, members of the Canadian Forces stationed abroad and all Canadian crew members of merchant vessels.

Collection methods

To ensure the best possible coverage, the country was divided into small geographic areas called collection units (CUs). In the 2006 Census, there were approximately 50,000 collection units.


In 2006, approximately 98% of households self-enumerated either online, or by completing the paper questionnaire. Respondents were asked to provide information for all members of the household, as it pertained to Census Day, May 16.

If the questionnaire was completed on paper, the respondent returned it by mail, in a pre-addressed yellow envelope, to the centralized Data Processing Centre. The questionnaire was then scanned and verified for completeness through an automated process.

If a questionnaire was completed and returned online, the information was directly submitted into the Data Processing Centre system and was verified for completeness.

Online questionnaire

Picture of hands on a keyboard

For the first time, the 2006 Census offered all households in Canada the option of completing their questionnaire online. This easy, secure and convenient option could be used anywhere, anytime, and was available in English and French.

Each paper questionnaire had a unique Internet access code printed on the front along with the 2006 Census website address ( Respondents needed this access code to do their questionnaire online.

This security feature made it secure, simple and quick for everyone to complete their census questionnaire online.

The census web application generated a confirmation number that the respondent was to retain as a proof of completion of the census questionnaire over the Internet.

This online collection method allowed the census data to be processed more quickly than those collected from paper questionnaires.

Collection support

To support the 2006 Census collection activities, an extensive communications program was established. In addition, the Census Help Line (CHL), a free, nationwide, multilingual service, was available to all respondents. The toll-free number was printed on the census questionnaire and guide, and advertised in all communications materials. The Census Help Line handled approximately 1,200,000 calls during the 2006 Census.

Census Communications Project

The goal of the 2006 Census Communications Project was to make all residents of Canada aware of the census, that everyone had the option of completing the census questionnaire online or by mail, that it was important and confidential and that there was a legal obligation to complete it.

'Count yourself in!' was the slogan. Communications materials highlighted important uses of the census such as:

  • the development of estimates which are used to calculate transfer payments from the federal government to the provinces and territories
  • the decision making process at national and provincial levels, as well as at the local community and neighbourhood levels
  • the provision of services such as schools, hospitals, transportation and fire stations at the community level.

After May 16, Census Day, people were also informed that participation in the census is required by law.

The Census Communications Program had the following five components:

Third-party support

Promotional support for the census was enlisted from national and regional corporations, associations, all levels of government including federal, provincial, territorial and municipal, as well as local community groups. Approximately 2,500 supporters included the census message in their regular correspondence with employees and clients, or posted a promotional banner or message on their website, linking to the census website at Statistics Canada. More than 2.2 billion messages were sent to respondents as a result of this program.

Media relations

Because the census is news, the media are instrumental in getting the census message out to the residents of Canada on a daily basis before, on, and after Census Day. By means of interviews with Statistics Canada spokespersons, and of editorials and stories, the 2006 Census received extensive coverage in the media, with more than 4,000 articles, both print and broadcast, in May 2006.


Educational activities were mostly directed at elementary and secondary students. The 2006 Census teacher's kit, containing assorted activities and materials that reinforced the importance of the census, was provided, free of charge, to about 18,000 educators, in paper format or online. Additional materials, including a map provided by Natural Resources Canada, a colouring book and a game activity placemat were also available.

Activities for English and French as a second language (ESL/FSL) learners were an important component, since students who read English or French better than their parents can help them complete the census form. An Adult basic education (ABE) kit was used extensively in classes for adults learning English or French and by literacy groups.

Paid advertising

The 2006 Census Advertising Program primarily used radio, supported by out-of-home media placements. Five population scripts and four agriculture scripts were initially prepared for the radio ads. An additional population script was prepared in August when it became apparent that a tougher message was required.

These messages were targeted to various sectors during the collection cycle and were used from May 1 to mid-August.

The out-of-home ads featured the yellow envelope along with a red mouse to symbolize the online census. These ads were located in areas with slow returns in the 2001 Census.

The advertising campaign was split into three phases, with the pre-census phase starting on May 1 and running to May 15; the second phase starting on May 17 and running to May 22 (no ads ran on May 16); and the final phase starting on May 22 and running to the second week of July. Additional advertising was spot-purchased in August for slow return areas.

Limited television coverage in languages other than English and French was used for messages to ethnic and immigrant communities. The ads were also fed to all networks, and used in English and French as public service announcements.

Special target populations

Hard-to-reach groups that were undercounted in the 2001 Census were targeted in the 2006 Census with communications strategies suitable to their situation. These groups included people who speak neither of the official languages, people with visual disabilities, people with low levels of literacy, seniors, students, the homeless, immigrants, Aboriginal people, young men and, in some areas, young women, between the ages of 18 and 30.

Communications activities for these groups included third party support, paid advertising, education, media relations and development of special materials.

A couple of seniors, a man and a woman, kick and laugh their way through fallen leaves during an autumn walk.

2006 Census processing

Receipt and registration

Respondents completing paper questionnaires mailed them back to a centralized data processing centre. Canada Post registered their receipt automatically by scanning the barcode on the front of the questionnaire through the see-through portion of the return envelope. The envelopes were then transported to the Data Processing Centre along with a CD containing the list of all of the identifiers for the registered questionnaires.

Responses received through the Internet or the Census Help Line telephone interview were received directly by the Data Processing Centre and their receipt registered automatically.

The registration of each returned questionnaire was flagged on the Master Control System at Statistics Canada. About 10 days after Census Day, a list of all of the dwellings for which a questionnaire had not been received was generated by the Master Control System and then transmitted to Field Operations for follow-up. Registration updates were sent to Field Operations on a daily basis to prevent follow-up on households which had subsequently completed their questionnaire, either by telephone or through the Internet.

Imaging and data capture from paper questionnaires

The 2006 Census was Canada's first census to capture data using automated capture technologies rather than manual keying.

Steps in imaging

  • Document preparation – mailed-back questionnaires were removed from envelopes and foreign objects, such as clips and staples detached in preparation for scanning. Forms that were in a booklet format were separated into single sheets by cutting off the spine.
  • Scanning – scanning, using 18 high-speed scanners, converted the paper to digital images (pictures).
  • Automated image quality assurance – an automated system verified the quality of the scanning. Images failing this process were flagged for rescanning or keying from paper.
  • Automated data capture – optical mark recognition and optical character recognition technologies were used to extract respondents' data from the images. Where the systems could not recognize the handwriting with sufficient accuracy, data repair was done by an operator.
  • Check-out – as soon as the questionnaires were processed successfully through all of the above steps, the paper questionnaires were checked out of the system. Check-out is a quality assurance process that ensures the images and captured data are of sufficient quality that the paper questionnaires are no longer required for subsequent processing. Questionnaires that had been flagged as containing errors were pulled at check-out and reprocessed as required.

Edits and failed edit follow-up

At this stage, a number of automated edits were performed on the respondent data. These edits simulated those that enumerators would have done manually in previous censuses. They checked for completeness of the responses as well as coverage (e.g., the number of persons in the household).

Data from questionnaires that failed the edits were forwarded to a processing clerk for verification against the image if available (online questionnaires would not have an image). If multiple questionnaires were received for one household, they were also verified at this stage to determine if they were duplicates (e.g., a husband completed the Internet version and his wife filled in the paper form and mailed it back).

In cases where the processing clerk could not resolve an error, or there were too many missing responses, the data were transmitted to a Census Help Line for follow-up. An interviewer telephoned the respondent to resolve any coverage issues and to fill in the missing information, using a computer-assisted telephone interviewing application. The data were then sent back to the Data Processing Center for reintegration into the system for subsequent processing.


The 2B long-form questionnaire contained questions where answers could be checked off against a list, as well as questions requiring a written response from the respondent in the boxes provided. These written responses underwent automated coding to assign each one a numerical code, using Statistics Canada reference files, code sets and standard classifications. Reference files for the automated match process were built using actual responses from past censuses. Specially trained coders and experts resolved cases where a code could not be automatically assigned. The variables for which coding applied were: Relationship to person 1; Place of birth; Citizenship; Non-official languages; Home language; Mother tongue; Ethnic origin; Population group; Indian band/First Nation; Place of residence 1 year ago; Place of residence 5 years ago; Major field of study; Location of study; Place of birth of parents; Language at work; Industry; Occupation and Place of work.

Over 40 million write-ins were coded from the 2006 long questionnaires; an average of about 75% of these were coded automatically.

Edit and imputation

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

After the capture, completeness, coverage editing, corrections and coding operations were completed, the data were processed through the final edit and imputation activity, which was almost fully automated. In general, the editing process detects the errors, and the imputation process corrects them.


Questions on age, sex, marital status, mother tongue and relationship to Person 1 were asked of 100% of the population, as in previous censuses. However, the bulk of census information was acquired on a 20% sample basis, using the additional questions on the 2B questionnaire. Weighting was 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 employed the same methodology used in the 2001 Census, known as calibration estimation. This began with initial weights of approximately 5 and then adjusted 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) and the population counts for age, sex, marital status, common-law status and household.

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

Master Control System

The automated processes, implemented for the 2006 Census, had to be monitored to ensure that all Canadian residences were enumerated once and only once. The Master Control System was built to control and monitor the process flow. The Master Control System held a master listing of all the dwellings in Canada (each dwelling was identified with a unique identifier and about two-thirds of the dwellings also had an address). This system was updated, on a daily basis, with information of each dwelling's status in the census process flow (i.e. delivered, received, processed, etc.). Reports were generated and accessible online to the census managers to ensure that operations were efficient and effective.

Data quality measurement

Throughout the census-taking process, every effort was made to ensure that the results would be of superior quality, while taking into consideration trade-offs between accuracy, cost, timeliness and respondent burden. Although it is impossible in any survey or census to eliminate all errors, they were minimized using rigorous quality standards for collecting and processing the data and activities such as the communications program which helped reduce non-response. Data quality measurement activities were undertaken to assess the overall quality of the census data. The quality of the data was measured in order to provide users with information about the reliability of the data, to improve data quality in future censuses and, in the case of estimates of coverage error, to adjust official population estimates. For more information on this subject, see Data quality.


Adapting a product line through consultation with data users

As with the previous 2006 Census consultation, this second round of consultations integrated discussions on the dissemination program, questionnaire content and census geography. However, the focus of this second round of consultations was placed on the 2001 Census of Population dissemination program and proposed directions for 2006 geography. Consultations were held from January to June 2004. Approximately 1,000 comments were captured through written submissions and the organization of over 40 meetings across Canada.

Marketing of products and services

Statistics Canada communicates, promotes, and informs clients of appropriate opportunities to maximize awareness of census data. This is achieved, in part, by:

  • planning and co-ordinating the releases of census data and specific products
  • developing a market sector approach for the promotion of the census data
  • maintaining contact with, and providing services to, previous census clients, as well as those who supplied financial sponsorship to the census collection activities
  • providing sales support and training workshops to new and existing users of census data.

Users will have access to more 2006 Census information free of charge on the Internet through Statistics Canada's website ( Each release of data continues to be summarized and published on Statistics Canada's website, with some analysis in The Daily. Eight official 2006 Census data releases are scheduled between March 13, 2007 and May 1, 2008.


  1. Only the 2A and 2B census questionnaires were produced in large print.

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