Guide to the Census of Population, 2021
Chapter 7 – Field operations


During the data collection phase, the objective was to ensure that responses were obtained from all households in Canada. Field operations included: listing dwellings, delivering invitation letters, determining the occupancy status of a dwelling and conducting interviews with non-respondents.

Census delivery methods

For most private dwellings, respondents were asked to complete the questionnaire for themselves and all members of the household.

On May 3, 2021, all private dwellings in the mail-out (MO) areas (approximately 86% of private dwellings in Canada) received by mail a bilingual invitation letter to complete the questionnaire online. As in 2016, this letter contained a secure access code (SAC), the web address of the 2021 Census website, and a telephone number to allow the respondent to request a paper questionnaire if they preferred.

In list/leave (L/L) areas, which represent 7% of dwellings, census employees dropped off an invitation letter. L/L door-to-door delivery took place from May 3 to May 10, 2021. During the L/L operation, census employees listed all private dwellings in specific areas in their Visitation Record. The invitation letter had a SAC so that respondents could fill out the questionnaire online. Paper questionnaires were available upon request, using a toll-free number. In the L/L areas, it was necessary for the respondent to provide a mailing address to an operator in order for the paper questionnaire to be mailed.

In 2021, the mail-out with drop-off (MODO) methodology was introduced. MODO areas are those where all dwellings have addresses, the majority of which are mailable. In these mixed areas, those dwellings with a valid mailing address were mailed the regular MO material (just like the MO areas), while those that did not have a valid mailing address (that correspond to the civic address) received an invitation letter dropped at their door by a census employee. The MODO areas were introduced to maximize the number of census MO dwellings. MODO areas represent more than 6% of the dwellings, and allowed an increase in the use of the MO methodology to extend to about 90% of dwellings (82% in 2016).

Traditionally, the remaining dwellings, located in First Nations communities, Métis settlements, Inuit regions and other remote areas, are enumerated in-person using canvasser methods. However, for the first time in 2021, all First Nations communities, Métis settlements, Inuit regions and other remote areas were offered the opportunity to self-respond, provided it was operationally feasible (i.e., Internet was accessible in the community). Depending on the situation, the invitation letter of the MO, L/L or MODO methodology was used (with minor changes, e.g., the paper questionnaire option was not offered), followed by non-response follow-up. Households in areas where it was not operationally feasible to offer self-response completed their census questionnaire with a census employee (in person or over the phone). In 2021, dwellings in remote, northern and Indigenous communities represent about 1% of dwellings in Canada.

Census wave approach

Statistics Canada implemented a wave approach for the 2021 Census, which consisted of reminding Canadians to fill out their questionnaire by various contact methods at specific times throughout the collection period. It also encouraged respondents to complete their questionnaire online, while mitigating the risk of a decline in overall response by also offering other response options such as ordering a paper questionnaire. The following table outlines the key dates for the different waves.

Table 7.1
Census collection phases and schedule
Table summary
This table displays the results of Census collection phases and schedule . The information is grouped by Collection phase (appearing as row headers), Main activity, Coverage and Start date (appearing as column headers).
Collection phase Main activity Coverage Start date
Wave 1—Invitation letter Dwellings in MO areas received an invitation letter with a SAC. All MO dwellings, including those in MODO areas (90% of all dwellings) May 3, 2021
Dwellings in L/L areas and drop-off dwellings in MODO areas received an invitation letter with a SAC. All L/L dwellings and drop-off dwellings in MODO areas (9% of all dwellings) May 3, 2021
Wave 2—Reminder letter or card Dwellings in MO areas received a reminder letter with a SAC. All non-responding MO dwellings, including those in MODO areas May 12, 2021
Dwellings in L/L areas received a reminder card. All L/L dwellings May 12, 2021
Wave 3—Second reminder letter Dwellings in MO areas received a second reminder letter with a SAC. All non-responding MO dwellings, including those in MODO areas May 21, 2021
Reminder message Dwellings in MO areas received either a text reminder (when a cellphone number was available), a voice broadcast message (if a landline phone number was available), or an email reminder (if an email address was available). All non-responding MO dwellings, including those in MODO areas May 30, 2021
Non-response follow-up NRFU began in L/L areas with telephone calls or in-person visits. All non-responding L/L dwellings May 21, 2021
NRFU began in MO and MODO areas with telephone calls or in-person visits. All non-responding MO and MODO dwellings June 2, 2021
Final notice letter Dwellings in MO areas received a final notice reminder letter with a SAC. All non-responding MO dwellings, including those in MODO areas July 13, 2021

In First Nations communities, Métis settlements, Inuit regions and other remote areas, depending on the situation, an invitation letter was delivered, by mail or in person, followed by non-response follow-up, which started on May 14, 2021. Starting on August 3rd, a reminder letter was also delivered to non-responding households in mail-out (MO) areas. If Internet was not available, questionnaires were completed in-person with a census employee from Statistics Canada starting on May 3, 2021.

Enumeration of collective dwellings

A collective dwelling refers to a dwelling of a commercial, institutional or communal nature in which a person or group of persons reside or could reside. It must provide care or services or have certain common facilities, such as a kitchen or bathroom, which are shared by the occupants. Examples include lodging or rooming houses, hotels, motels, tourist establishments, nursing homes, residences for senior citizens, hospitals, staff residences, military bases, work camps, correctional facilities and group homes.

Collection procedures for the 2021 Census were redesigned to ensure respondents and census employees were safe by limiting the amount of contact needed to participate in the census. No census employee from Statistics Canada was permitted to visit or enter institutional collective dwellings, especially the dwellings housing residents who are vulnerable to COVID-19, such as residences for senior citizens and hospitals. For more information about the impact of COVID-19 on the 2021 Census of Population, refer to Appendix 1.4 Impact of the COVID-19 pandemic.

For the 2021 Census, collective dwellings were enumerated using one of the following methods:

Electronic questionnaire

For most collective dwellings, the 2021 Census: Collective Dwellings electronic questionnaire was used to collect information on the facility and its usual residents. In April 2021, invitation letters or emails containing a SAC were sent to the administrators of the collective dwellings for online response. Shortly after the invitation letters or emails were sent, non-response follow-up started. Administrators could therefore either self-respond through online collection or they would receive telephone follow-up calls to complete the questionnaire with an interviewer.

For institutional collective dwellings, administrators were required to complete a series of questions about their facility and complete the census about residents of the facility. If the facility maintained electronic records containing information required to answer the census questions (e.g., age, sex at birth, gender, languages), then they attached their records electronically in any format, even if some of the information was not available. Alternatively, they downloaded a standard electronic template and answered the census questions for each usual resident according to their knowledge. In addition to providing information on the usual residents of their facility, administrators were also required to provide sociodemographic information on the residents of private dwellings attached to the collective dwelling (see box below). A standard electronic template was used to collect this information as well.

Private dwelling attached to collective dwelling

A collective dwelling may sometimes have one or more attached private dwelling(s).

A private dwelling that is located within the collective grounds or attached to the collective dwelling structure is considered a private dwelling attached to a collective dwelling.

This includes only dwellings:

  • with the same civic address as the collective dwelling, but with a different apartment or unit number
  • that are not part of the commercial, institutional or communal purpose of the collective dwelling (i.e., persons in these dwellings do not receive any care or services from the facility)
  • that are not occupied by live-in employees, owners or managers.


Alternative arrangements were made for some types of dwellings in which there is no administrator present or where there were no available electronic records. In these cases, when census employees made in-person visits, a new no-contact protocol was followed. Under this protocol, census employees remained physically distanced, and they were required to wear personal safety equipment, in accordance with guidelines from public health authorities.

For lodging or rooming houses and Hutterite colonies (types 60 and 80), field visits were conducted. Census employees contacted the administrators of rooming or lodging houses and representatives of Hutterite colonies starting on May 3, 2021. For lodging and rooming houses, data were collected via personal interviews, using 3A questionnaires. For Hutterite colonies, census employees dropped off 2A questionnaires to be completed by the households living in the colony, and they returned to collect the questionnaires at a later date.

Usual resident head count

For establishments with temporary accommodation services (e.g., hostels, hotels, campgrounds, YMCA/YWCA) and other establishments—including school residences, military bases and work camps— administrators were required to provide only the count of usual residents. When the administrator could not provide this information online, a census employee followed up with them by phone. If the number of usual residents still could not be provided, census cards were dropped off for respondents to self-identify as usual residents of the establishment. Administrators were also required to provide the full address (including unit number) of the private dwellings attached to the collective dwelling. These private dwellings were then mailed an invitation letter containing a SAC to complete their own census questionnaire online.

Administrative data

Statistics Canada replaced traditional enumeration for some correctional or custodial facilities with administrative data from the Canadian Correctional Services Survey (CCSS). The CCSS collects and validates a variety of information on persons supervised by a correctional services program. If an institution was not reporting their data, Statistics Canada attempted to obtain the data via an electronic transfer. When both methods were not available, a letter or email with a secure access code was sent to the administrator of the institution for online response.

The table below provides a summary of the collection methods used for collective dwellings.

Table 7.2
Collection method by collective dwelling type
Table summary
This table displays the results of Collection method by collective dwelling type. The information is grouped by Collection method (appearing as row headers), Collective dwelling type (appearing as column headers).
Collection method Collective dwelling type
Electronic questionnaire


administrative data through the CCSS
for some of the collective dwellings of type 50
10 – Hospital
20 – Nursing home or residence for senior citizens
30 – Residential care facility such as a group home for persons with disabilities or addictions
40 – Shelter
50 – Correctional or custodial facility
70 – Religious establishment such as a convent, monastery or seminary
Field collection (3A questionnaire) 60 – Lodging or rooming house
Field collection (2A questionnaire) 80 – Hutterite colony
Electronic questionnaire
field collection (telephone calls or
in-person visits using 7B cardsTable 7.2 Note 1)
90 – Establishment with temporary accommodation services such as a hotel, campground, YMCA/YWCA, Ronald McDonald House or hostel
91 – Other establishment such as a school residence, military base, work camp or vessel

Census Help Line

The Census Help Line, a free, nationwide, multilingual service, was available to all respondents. The toll-free number was advertised in all census communications materials.

Occupancy verification and follow-up activities for the 2021 Census

Apartment occupancy verification—The purpose of apartment occupancy verification (AOV) was to verify the occupancy status of all units in an apartment building through one management contact. The information was collected through a telephone interview with the contact person. This contact person could be the owner of the building, or the superintendent or the building manager, for instance. AOV is an important activity, because it helped produce a more accurate status of occupancy for these types of dwellings, and it reduced the workload of the census non‑response follow-up (NRFU) activity. AOV was conducted by Collection Support Unit operators from May 10 to 18, 2021.

Dwelling occupancy verification—For a sample of dwellings in mail-out (MO) areas, the status of occupancy was verified immediately before NRFU. Dwelling occupancy verification was conducted from May 21 to 28, 2021, to identify as many unoccupied or cancelled dwellings as possible close to Census Day to remove these dwellings from the NRFU workload. The accuracy of the occupancy status is higher if identified closer to Census Day. This operation is independent from the AOV described above.

Non-response follow-up—The purpose of NRFU was to obtain a completed questionnaire from all households that did not return a questionnaire. Follow-up was done via telephone or in-person visits. In list/leave areas, follow-up was conducted from May 21 to August 13, 2021, and in the MO and mail-out with drop-off areas from June 2 to August 13, 2021. In canvasser and reserve areas, NRFU was conducted from May 14 to September 24, 2021. If Internet was not available, questionnaires were completed in-person with a census employee starting on May 3, 2021.

The failed edit follow-up (FEFU) operation is the process of contacting, by telephone, respondents that have filled out their questionnaire in order to clarify inconsistent or invalid answers or to resolve missing and incomplete responses. FEFU was conducted from Statistics Canada regional offices from May 10 to August 14, 2021. It was primarily focused on cases with potential household composition issues.

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