Type of Dwelling Reference Guide, Census of Population, 2021

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Definitions and concepts

The census counts people in the dwelling in which they usually live to ensure that a person is enumerated once and only once. People are counted in their usual place of residence.

There are two types of dwellings in the census—private dwellings and collective dwellings. Private dwellings can be broken down into regular dwellings and marginal dwellings occupied by usual residents. Regular dwellings are further classified into three categories—private dwellings occupied by usual residents, unoccupied private dwellings, and private dwellings occupied by foreign residents and/or by temporarily present persons.

Structural type of dwelling refers to the structural characteristics and dwelling configuration. This dwelling characteristic variable is collected for all private dwellings in Canada.

For more information on the dwelling population of interest, including an illustration of the dwelling categories used in the 2021 Census of Population (Figure 2.1), see the Dictionary, Census of Population, 2021, Statistics Canada Catalogue no. 98-301-X.

Questions

For the 2021 Census, the 2A short-form questionnaire was used to enumerate all usual residents of 75% of private dwellings. The 2A-L long-form questionnaire, which also includes the questions from the 2A short-form questionnaire, was used to enumerate a 25% sample of private households in Canada. For private households in First Nations communities, Métis settlements, Inuit regions and other remote areas, the 2A-R questionnaire was used to enumerate 100% of the population.

Structural type of dwelling

The questionnaires for the 2021 Census of Population have no specific questions that collect information on the structure of each dwelling. Rather, information on the structural type of a dwelling is collected by trained employees both during and between censuses. A picture representation of the structural type of dwelling—and its definition—is supplied to enumerators. This helps ensure consistency in the classification process across Canada. The following diagrams are some of the tools used to assign structural type:

Single-detached house (Code 1)

A single dwelling not attached to any other dwelling or structure (except its own garage or shed). A single-detached house has open space on all sides, and has no dwellings either above or below it.

A mobile home fixed permanently to a foundation should be coded as a single-detached house (see Code 8).

Semi-detached house (Code 2)

One of two dwellings attached side by side (or back to back) to each other, but not to any other dwelling or structure (except its own garage or shed). A semi-detached dwelling has no dwellings either above or below it, and the two units together have open space on all sides.

Row house (Code 3)

One of three or more dwellings joined side by side (or occasionally side to back), such as a townhouse or garden home, but not having any other dwellings either above or below.

If row houses are attached to high-rise buildings, assign Code 3 to each townhouse.

Apartment or flat in a duplex (Code 4)

One of two dwellings located one above the other. If duplexes are attached to triplexes, other duplexes or other non-residential structures (e.g., a store), assign Code 4 to each apartment or flat in the duplexes.

Apartment in a building that has five or more storeys (Code 5)

A dwelling unit in a high-rise apartment building that has five or more storeys.

Also included are apartments in a building with five or more storeys where the first floor or second floor is commercial establishments.

Apartment in a building that has fewer than five storeys (Code 6)

A dwelling unit attached to other dwelling units, commercial units or other non-residential space in a building that has fewer than five storeys.

Other single-attached house (Code 7)

A single dwelling that is attached to another building and that does not fall into any of the other categories, such as a single dwelling attached to a non-residential structure (e.g., a store or church) or occasionally to another residential structure (e.g., an apartment building).

Mobile home (Code 8)

A single dwelling designed and constructed to be transported on its own chassis and capable of being moved to a new location on short notice. It may be placed temporarily on a foundation such as blocks, posts or a prepared pad and may be covered by a skirt.

A mobile home must meet the following two conditions:

• It is designed and constructed to be transported on its base frame (or chassis) in one piece.
• The dwelling can be moved on short notice. This dwelling—because of the nature of its construction—can be relocated easily to a new location by disconnecting it from services, attaching it to a standard wheel assembly and moving it without resorting to significant renovations and reconstructions.

Other movable dwelling (Code 9)

A single dwelling, other than a mobile home, used as a place of residence, but capable of being moved on short notice, such as a tent, recreational vehicle, travel trailer, houseboat or floating home.

Collective dwelling

Collective dwellings are classified using data collected with the Collective Dwelling Record, Form 1A. This form provides an overview of the collective dwelling, including the total number of usual residents and the type of collective being enumerated. To create the more detailed classification of collective dwellings, an administrator of each collective dwelling is asked a series of auxiliary questions regarding the level of care and services provided at the collective dwelling. Based on this information, the appropriate collective dwelling classification is assigned.

For more information on the reasons why the census questions are asked, please refer to the five fact sheets found on The road to the 2021 Census web page.

Classifications

Structural type of dwelling

The variable for structural type of dwelling classifies private dwellings into the following nine mutually exclusive categories: single-detached house, semi-detached house, row house, apartment or flat in a duplex, apartment in a building that has five or more storeys, apartment in a building that has fewer than five storeys, other single-attached house, mobile home, and other movable dwelling. The Census Dictionary provides a definition for each structural type of dwelling.

Collective dwelling

The 2021 Census also collects information on collective dwelling type. Collective dwellings are organized into 10 broad categories: hospital, nursing home or residence for senior citizens, residential care facility, shelter, correctional institution or custodial facility, lodging or rooming house, religious establishment, Hutterite colony, establishment with temporary accommodation services, and other establishment. These categories were established based on the level of care and services provided to residents. Data on the types and levels of care and services offered are used to derive a more detailed classification of collective dwellings. The Census Dictionary provides a definition for every type of collective dwelling.

Collective dwellings can also be classified as institutions or non-institutions. These classifications are used to create the institutional resident indicator, which is used for some census data products. The distinction between institutional and non-institutional collective dwellings is described in the Census Dictionary.

Concepts over time

Concepts and classifications relating to the structural type of dwelling have remained constant since 2006.

In censuses prior to 2021, shelters were classified into one of three groups based on their clienteles (i.e., shelter for homeless persons, shelter for abused women and their children, and shelter for ex-inmates in halfway houses). As a result of further analysis of the “other - specify” responses from 2016, a new type of shelter was added to the Form 1A—shelter for refugees and asylum seekers.

Collection and processing methods

The COVID-19 pandemic emerged in Canada in early 2020 and affected all steps of the 2021 Census process, from data collection to dissemination. Please refer to the Guide to the Census of Population, 2021, Statistics Canada Catalogue no. 98-304-X for more detailed information on this topic.

Prior to the 2021 Census of Population, data pertaining to collective dwellings and their residents were collected by census employees. Because of the COVID-19 pandemic, collection procedures for the 2021 Census were redesigned to ensure the safety of respondents and census employees and limit contacts. Census employees did not visit any institutional collective dwellings, such as hospitals, nursing homes and residences for senior citizens, or any long-term care facilities. Administrators of institutional collective dwellings answered a series of questions about their facility and provided census information on their usual residents using the 2021 Census: Collective Dwellings, electronic questionnaire.

Data quality

The 2021 Census of Population underwent a thorough data quality assessment. The different certification activities conducted to evaluate the quality of the 2021 Census data are described in Chapter 9 of the Guide to the Census of Population, 2021, Statistics Canada Catalogue no. 98-304-X.

The data quality assessment was conducted in addition to the regular verifications and quality checks completed at key stages of the census. For example, throughout data collection and processing, the accuracy of specific steps such as data capture and coding was measured, the consistency of the responses provided was checked, and the non-response rates for each question were analyzed. As well, the quality of imputed responses was assessed during data editing and imputation.

During the data quality assessment, a number of data quality indicators were produced and used to evaluate the quality of the data. These indicators are briefly described below. Finally, resulting census counts were compared with other data sources and certified for final release.

The main highlights of this assessment of the data pertaining to type of dwelling are presented below.

Data quality indicators

A number of quality indicators were produced and analyzed during the 2021 Census of Population data quality assessment. Three indicators are available to data users for short-form content: the total non-response (TNR) rate, as well as the non-response rate and imputation rate per question.

The total non-response (TNR) rate is the primary quality indicator that accompanies each disseminated 2021 Census of Population product, and is calculated for each geographic area. It measures total non-response at the dwelling level. Non-response is said to be total when no questionnaire is returned from a dwelling or when a returned questionnaire does not meet the minimum content. More information on the TNR rate is available in Chapter 9 of the Guide to the Census of Population, 2021, Statistics Canada Catalogue no. 98-304-X.

Partial non-response is when answers to certain questions are not provided for a respondent household.

The non-response rate per question is a measure of missing information due to non-response to a question. For the short-form questionnaire, the non-response rate per question includes both TNR and partial non-response to the question.

It is defined as the total number of in-scope units for which no response was provided to the question, divided by the total number of in-scope units for the question. Here “units” refers to the statistical units for which data are collected or derived (e.g., persons or households, depending on whether the question is about a person-level characteristic or a household-level characteristic). A unit is considered to be in scope if it belongs to the census target population (i.e., private and collective dwellings occupied by usual residents) and if the question is applicable to that unit.

The imputation rate per question measures the extent to which responses to a given question were imputed. Imputation is used to replace missing data in the event of non-response or when a response is found to be invalid (e.g., multiple answers are provided when a single answer is expected). Imputation is conducted to eliminate data gaps and to reduce bias introduced by non-response. Imputation is generally done by identifying persons or households in the same geographical area with similar characteristics to the incomplete record and copying their values to fill in the missing or invalid responses.

The imputation rate per question is defined as the total number of in-scope units for which the response to that question was imputed, divided by the total number of in-scope units (see the definition of “units” provided in the above section on the non-response rate per question). For short-form content, imputation resolves both total and partial non-response (weighting is not done to adjust for total non-response, as it is for long-form content). Whole household imputation (WHI) is used to resolve total non-response. It first imputes the occupancy status of non-respondent dwellings and further imputes all the data for those dwellings resolved as occupied in the first step. WHI is included in the imputation rate per question, including the use of administrative data to impute non-responding households in areas with low response rates; see Appendix 1.7 of the Guide to the Census of Population, 2021, Statistics Canada Catalogue no. 98-304-X. As with the non-response rate, a unit is considered to be in scope if the question is applicable to that unit and the unit belongs to the census target population.

The non-response and imputation rates for a question are often similar, but some differences can be observed for a given question because of additional data processing steps that may have been required. These rates were regularly checked during data assessment, and a detailed analysis was done if there was a difference between the two rates for a question, to ensure the appropriateness of the processing steps taken and the quality of the data. A difference between the non-response rate and the imputation rate for a question can generally be explained by one of the following two factors:

• Some responses were considered invalid or inconsistent during the edit stage and imputation was needed, which is why the imputation rate is higher than the non-response rate for a question.
• Some non-responses were resolved in a straightforward manner early during data processing because a single resolution was possible based on the answers provided to other questions, making imputation unnecessary. This may explain why the non-response rate is higher than the imputation rate for a question.

Tables 1 and 2 below present the non-response and imputation rates for Canada and each province and territory.

The non-response and imputation rates per question at lower levels of geography are also available in 2021 Census data tables presenting data quality indicators. This information is scheduled for release on August 17, 2022 for short-form questions (will include quality indicators for structural type of dwelling) and on November 30, 2022 for long-form questions.

Certification of final counts

Once data editing and imputation were completed, the data were tabulated to represent the total Canadian population. Certification of the final counts was the last step in the validation process, which led to the recommendation to release the data for each level of geography and domain of interest. Based on the analysis of the data quality indicators and the comparison of the census counts with other data sources, the recommendation is for unconditional release, conditional release, or non-release (for quality reasons on rare occasions). For conditional release or non-release, appropriate notes and warnings are included in the products and provided to users. Moreover, other data sources were used to evaluate the census counts. However, since the risk of error often increases for lower levels of geography and for smaller populations, and the data sources used to evaluate these counts are less reliable or not available at these lower levels, it can be difficult to certify the counts at these levels.

Census counts are also subject to confidentiality rules that ensure non-disclosure of respondent identity and characteristics. For more information on privacy and confidentiality, please refer to Chapter 1 of the Guide to the Census of Population, 2021, Statistics Canada Catalogue no. 98-304-X. For information on how Statistics Canada balances the protection of confidentiality and the need for disaggregated census data, with specific attention to new 2021 Census content, please refer to Balancing the Protection of Confidentiality with the Needs for Disaggregated Census Data, Census of Population, 2021, Statistics Canada Catalogue no. 98-26-0005.

Data quality for type of dwelling variables

The evaluation process for the type of dwelling variables consisted of the following activities:

• evaluation of collection procedures
• examination of the total imputation rates for structural type of dwelling and collective dwelling
• examination of the non-response for collective dwellings
• historical comparison with data from previous censuses
• comparison with other sources of data where applicable.

To assess the fitness for use of the 2021 Census of Population data for a particular user’s needs, and to understand the risks involved in drawing conclusions from or making decisions on the basis of these data, users should be aware of the following data quality indicators for the dwelling variables.

Structural type of dwelling

For the 2021 Census, the information for structural type of dwelling was validated or updated for approximately 15% of private dwellings during the listing, census collection and field operation activities leading up to Census Day. For the remaining 85% of dwellings, the dwelling structural type is based on field operations supporting the previous censuses. The areas that were not field validated as part of the 2021 Census were generally the most stable across the data holdings of Statistics Canada’s dwelling register. As a result, the quality of the structural type of dwelling information is still considered of high quality.

About 6.8% of the records for the structural type of dwelling were blank after listing and field activities, and required imputation for the 2021 Census of Population. These records consisted mainly of new dwellings that had not been listed and got assigned a missing code (i.e., non-response). The expansion of mail-out and the introduction of the mail-out with drop-off collection methodology, as well as the significant decrease in field listing activities because of the COVID-19 pandemic, resulted in a higher imputation rate compared with the last cycle (3% in 2016). For more detailed information on the collection methods, please refer to the Guide to the Census of Population, 2021, Chapter 7 – Field operations.

Imputation and non-response rates for the structural type of dwelling by province and territory can be seen in Table 1 below.

Collective dwelling

Because of the COVID-19 pandemic, collection methods and processing procedures for the 2021 Census of Population were redesigned to limit the amount of contact needed to participate in the census to ensure respondents and census employees were safe. In this context, changes in collection procedures for collective dwellings may have had an impact on the historical comparability of collective dwelling data, as outlined in this section. Because of this, caution must be used when making a historical comparison. Additional analysis of the measurement of collective dwellings and the unique context of 2021 collection will be conducted and publicly disseminated.

In previous census cycles, collective dwellings were identified and classified by census employees who spoke with the administrator or other designated official of the facility. In addition, census employees would collect data pertaining to residents. If they were unable to collect data, they were still able to validate the status of the collective dwelling during the field visit (e.g., a cancelled listing, unoccupied collective dwelling or refusal to participate).

For the 2021 Census of Population, census employees did not visit any institutional collective dwellings, such as hospitals, nursing homes, long-term care facilities, residences for senior citizens or religious establishments. Administrators of these facilities were required to complete a series of questions about their facility using the 2021 Census: Collective Dwellings electronic questionnaire. To reduce the number of unresolved cases at the end of collection, more resources were deployed for telephone follow-up, reminder letters were sent or mailed to administrators and the collection period was extended.

Statistics Canada replaced traditional enumeration for correctional and custodial facilities with administrative data available 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 data were not reported by an institution, Statistics Canada attempted to obtain the data via an electronic transfer. When neither of these methods were applicable, a letter or email with a secure access code was sent to the administrator of the institution for online response.

Data for persons in these correctional and custodial facilities were provided, and usual residents were determined via a record linkage of the administrative data with the census data for the population living in private dwellings. This was the first time a record linkage was completed for individuals in these facilities, and it was done only for this type of collective dwelling. This method was implemented following an undercoverage study of 2016 Census data for this population. This analysis showed that a significant proportion of persons in custody should have been counted in the 2016 Census but were not, reflecting that residency rules in the census could have been misinterpreted in some instances. The improved strategy for identifying usual residents of a correctional or custodial facility can contribute to apparent population growth in this category.

As for the 2016 Census, administrators of establishments with temporary accommodation services (e.g., hostels, hotels, campgrounds, YMCA–YWCA) and other establishments—including school residences, military bases and work camps—were required to provide only the count of usual residents. To reduce the number of in-person visits, efforts were made to collect the information online by sending an invitation letter to complete the census questionnaire online and following up by telephone. The online option was new for the 2021 Census. If the number of usual residents could not be provided, census cards were dropped off for respondents to self-identify as usual residents of the establishment, as in 2016.

For the 2021 Census, the number of foreign residents and temporarily present persons was collected for some collective dwellings. Consequently, this change has resulted in the combination of unoccupied collective dwellings and collective dwellings occupied solely by foreign residents or temporarily present persons. Furthermore, it is likely that some collective dwellings that were valid collective dwellings in 2016 were no longer considered operational in 2021 because they were temporarily or permanently closed as an effect of the COVID-19 pandemic. Similar to previous census years, data are disseminated only for collective dwellings occupied by usual residents.

For lodging or rooming houses and Hutterite colonies, field visits were conducted in a similar way to previous censuses. Because of COVID-19, when census employees made in-person visits, a new no-contact protocol was followed. Under this protocol, census employees remained physically distanced and were required to wear personal safety equipment in accordance with guidelines from public health authorities.

For the 2021 Census, 6.5% of collective dwellings had blank or invalid information on type of collective dwelling after collection activities and, as a result, required imputation to derive the detailed collective dwelling classification. This was done in processing using the responses recorded in Section 2 of the 2021 Census: 1A.

For collective dwellings occupied by usual residents, imputation rates for the type of collective dwelling at the national, provincial and territorial levels can be seen below in Table 2.

Comparability over time

Structural type of dwelling

The structural type of dwelling concept has remained relatively stable since the 1981 Census. Though there were no changes between the 2016 and 2021 censuses, there have been some adjustments to the concepts and classifications in earlier censuses. In 2011, additional classification information was added within definitions for “row house” and “apartment in a building that has five or more storeys.” Starting in 2006, “apartment or flat in a duplex” includes duplexes attached to other dwellings or buildings. Prior to the 2006 Census, duplexes attached to other dwellings or buildings were classified as an “apartment in a building that has fewer than five storeys.” Starting in 1981, dwellings in apartment buildings are classified in two categories: “apartment in a building that has five or more storeys” and “apartment in a building that has fewer than five storeys.” Previously, this distinction between the heights of apartment buildings was not available, and these types of dwellings were all classified as “apartments.” Since there are more variants in the classification of structural type of dwelling prior to the 1981 Census, users are cautioned to use census reference materials when making historical comparisons that predate the 1981 Census.

Comparisons of structural type of dwelling distributions for Canada between the 2011, 2016 and 2021 censuses in Table 3 show small variations in the share of dwelling types. For example, there is a decrease in the share for “single-detached house” (-1.0 percentage point) and an increase in the share for “apartment in a building that has five or more storeys” (+0.8 percentage points).

Collective dwelling

The collective dwelling concept and classification have remained the same since 2016. There were some adjustments to the classifications between 2011 and 2016.

An additional category was introduced in 2016 to classify facilities for senior citizens that offer extended health care services to some residents and support or assisted living services to other residents (e.g., a facility that is both a nursing home and a residence for senior citizens). Starting in 2016, bed and breakfasts were classified as private dwellings. Prior to 2016, bed and breakfasts were classified as collective dwellings and were included in the “hotels, motels and other establishments with temporary accommodations” category.

In 2011, residential care facilities were classified into one of three groups based on the main type of service provided at the facility. Starting in 2016, collection methods allowed for multiple responses to the different types of services provided at these facilities. As a result, residential care facilities are now assigned the same collective dwelling type value, and five additional flags indicate whether the facility provides one or more of the following services:

• services primarily for children or minors
• services for persons with psychological disabilities
• services for persons with physical challenges or disabilities
• services for persons with developmental disabilities
• services for persons with an addiction.

However, enumeration of collective dwellings underwent substantial changes in the 2021 Census, and this could potentially have an impact on historical comparability for some collective dwellings.

Comparability with other data sources

Structural type of dwelling

Some other surveys, including the Survey of Household Spending (SHS) and the Canadian Housing Survey (CHS), collect data on structural type of dwelling. The Canadian Income Survey (CIS) also collects this information, but the CIS is based on the Labour Force Survey sample file, while the CHS—like the census—uses data from Statistics Canada’s dwelling register. Data reported by respondents via a questionnaire may not always have the same level of detail as those recorded by trained enumerators during listing activities for the Census of Population. For this reason, users are advised to refer to the Census Dictionary, as well as any survey-specific metadata when comparing data on structural type of dwelling with data from other sources.

To facilitate comparisons of data on structural type of dwelling between the census and other datasets, some categories may need to be combined. When census counts are compared with the SHS estimates Table 4 and the CHS Table 5, the three sources produce similar distributions of structural types of dwelling. The share of apartments is slightly lower in the SHS than in the census, while the remaining distributions are relatively stable over time. The most notable difference between census data and the CHS is a slightly lower proportion of single-detached houses in the CHS.

The Canadian Housing Statistics Program (CHSP) collects information on residential properties and covers numerous aspects of the housing sector. The CHSP categorizes residential properties as follows:

• single-detached house
• semi-detached house
• row house
• condominium apartment
• mobile home
• other property type
• property with multiple residential units
• vacant land.

It should be noted that the CHSP and the census use different concepts and methodologies to produce data on housing. The population of interest for the CHSP is the residential property, while dwelling is that for the census. Also, the CHSP obtains housing statistics through a number of administrative data sources, including tax data, Business Register data, census data, and data from land registries and property assessment programs. The census obtains housing data from the dwelling register and the census questionnaire.

Collective dwellings

Users should be cautioned that the census collective dwelling types are not expected to always agree with classifications used in administrative data or other sources. In the census, some collective dwellings are classified by the types and levels of services offered rather than by their name or official status from a business or institutional perspective. Furthermore, census data are collected only for usual residents living in collective dwellings. While data for foreign residents or temporarily present persons are not collected in the census, these residents may be included in other administrative data sources.