Census tract: Detailed definition
Census tracts (CTs) are small, relatively stable geographic areas that usually have a population between 2,500 and 8,000 persons. They are located in census metropolitan areas and in census agglomerations that had a core population of 50,000 or more in the previous census.
A committee of local specialists (for example, planners, health and social workers, and educators) initially delineates census tracts in conjunction with Statistics Canada. Once a census metropolitan area (CMA) or census agglomeration (CA) has been subdivided into census tracts, the census tracts are maintained even if the core population subsequently declines below 50,000.
2011, 2006, 2001, 1996, 1991, 1986, 1981, 1976, 1971, 1966, 1961, 1956, 1951, 1941
Rules are used to delineate census tracts. The initial delineation rules are ranked in the order of the following priorities:
- Census tract (CT) boundaries must follow permanent and easily recognizable physical features. However, street extensions, utility or transportation easements, property lines and municipal limits may be used as CT boundaries if physical features are not in close proximity or do not exist.
- The population of a CT should range between 2,500 and 8,000, with a preferred average of 4,000. CTs in the central business district, major commercial and industrial zones, or peripheral areas can have populations outside this range.
- The CT should be as homogeneous as possible in terms of socioeconomic characteristics, such as similar economic status and social living conditions at the time of its creation.
- The CT's shape should be as compact as possible.
- CT boundaries respect census metropolitan area, census agglomeration and provincial boundaries. However, CT boundaries do not necessarily respect census subdivision (municipality) boundaries.
A complete set of delineation rules and operational procedures for census tracts are available upon request from the Geography Division, Statistics Canada.
Changes to census tract boundaries are discouraged in order to maintain maximum data comparability between censuses. Boundary revisions rarely occur, and only when essential. Road construction, railroad abandonment, community redevelopment, neighbourhood growth and municipal annexations may contribute to changes in census tract boundaries. A census tract may be split into two or more new census tracts (usually when its population exceeds 8,000). CT splits are usually done in a way that allows users to re-aggregate the splits to the original census tract for historical comparison.
The minimum population of 2,500 allows for statistically significant data tabulations. The maximum population of 8,000 facilitates delineation and retention of relatively homogeneous and useful tracts. The population range and average also permit data comparability among census tracts.
Naming convention for census tracts
Each census tract is assigned a seven-character numeric 'name' (including leading zeros, the decimal point and trailing zeros). To uniquely identify each census tract in its corresponding census metropolitan area (CMA) or tracted census agglomeration (CA), the three-digit CMA/CA code must precede the CT 'name'. For example:
|CMA/CA code – CT name||CMA/CA name|
|562 0005.00||Sarnia CA (Ont.)|
|933 0005.00||Vancouver CMA (B.C.)|
Census tract naming is consistent from census to census to facilitate historical comparability.
When a CA enters the census tract program, the census subdivision (CSD) that gives the CA its name is assigned the first CT 'name,' starting at 0001.00. When all of the CTs within the first CSD are named, then the CTs of the adjoining CSDs are named, and finally those on the periphery are named.
If a census tract is split into two or more parts due to a population increase, the number after the decimal point identifies the splits. For example, CT 0042.00 becomes CT 0042.01 and CT 0042.02. If CT 0042.01 is subsequently split, it becomes CT 0042.03 and CT 0042.04. Similarly, if CT 0042.02 is split after CT 0042.01, it becomes CT 0042.05 and CT 0042.06. Any splits occurring after this would be numbered in a similar fashion, with the next sequential number. This allows users to re-aggregate the splits to the original census tract.
Table 1 in the Introduction shows the number of census tracts by province and territory.
A conversion table showing the relationship between the current and previous census tracts for each tracted centre is available upon request from the Geography Division, Statistics Canada.
The nature of the census tract concept, along with the availability of a wide range of census data, makes census tracts useful in many applications. These include:
- municipal and regional planning and research, such as the development, evaluation and revision of official plans
- educational and research studies in high schools, community colleges and universities
- market research, such as identifying areas of opportunity and evaluating market or service potential for housing, health, educational, recreational or retailing facilities.
Census tracts should be used with caution for non-statistical purposes.
Changes prior to the current Census
Beginning in 1996, census agglomerations were eligible for census tracts based on the population size of their urban cores (50,000 or more at the previous census). This was a change from previous censuses, when census agglomerations had to contain a municipality (census subdivision) with a population of 50,000 or more at the previous census to be eligible for census tracts.
From 1971 to 1991, a provincial census tract program existed. Provincial census tracts were similar in concept to census tracts, but covered areas outside census metropolitan areas and census agglomerations. Taken together, census tracts and provincial census tracts covered all of Canada.
In 1941 and 1946, census tracts were called 'social areas.'