Denominator: Land Area (square kilometre)
Original source: Statistics Canada
Distributed by: Statistics Canada
Suggested citation (see Data Citation Notes): Community Profiles [year], Census [year], Statistics Canada, Date Extracted: [date]

• Number of ‘residents’ is used rather than ‘people’ as it is a standard definition of Statistic Canada.
• Other data sources exist that provide ‘land area’ (denominator) such as DMTI Spatial, and MPAC Property Assessments. However, these data sources require a nominal fee.
• Census tract (CT) and census dissemination area (DA) level data are available upon request from Statistics Canada.
• The land area unit of ‘per hectare’ is widely used by urban planners. When presenting results to planning groups, conversion from ‘per square km’ to ‘per hectare’ may be required for the ease of communication. However, the users should recognize that because a hectare is one hundredth of a squared km, the conversion assumes that all these subdivided areas of one hectare have the same population density, which is rarely true in reality. For public health practice, the use of ‘per square km’ is strongly recommended.
• One hectare is a unit of area equal to 10,000 square metres; also equivalent to 2.471 acres.
• One square kilometre (1km²) is equal to 100 hectares (ha).
• The population density indicator will be used to determine if an area is urban or rural. However, in some cases this may not be appropriate. For example, in calculating population density for a census tract area that has an airport, the estimated population density would be quite small. Hence, it would not be appropriate to classify it as rural.
• This indicator is an indicator for ‘gross’ density rather than ‘net’ density. Gross density includes the use of the entire land area in the calculation, where as net density excludes certain land uses in the area (such as bodies of water). Gross density is used more commonly as a measure of walkability as people walk in a total environment.^2,7,8
• When estimating land area as the denominator of population density, one is highly recommended to make use of census digital cartographic file, rather than census digital boundary file.  The difference between digital cartographic file and digital boundary file is that the former takes into account of natural features such as waters. A a result, it depicts more accurately the land areas that are inhabited.
• As densities are measured across higher levels of land area (municipality versus census tract), densities generally decrease as more non-residential land is included in the base land calculation.²
• In a small number of DAs (or enumeration areas in previous Census), DA data are suppressed by Statistics Canada to protect privacy because of small population counts in the DA. Thus, the population count (as well as the associated demographic attributes) may not necessarily reflect true values.
•  In comparison to DAs, CT boundaries are relatively constant. However, some CTs may be divided into smaller areas over time to reflect an increase in population. For example, the census tract of 535.7 (in Toronto) was considered as one CT in 1981 census, but it became two CTs in 1986 census (535.7.001 and 535.7.002). As a result, the calculation of population density should reflect these changes.³
• “Typically, higher densities of people mean higher densities of destinations.  More destinations lead to a higher likelihood that one’s destination of choice – or at least a satisfactory destination – will be within walking or cycling distance”. ^{2, 4}
• If dissemination area (DA) level geography is used for land use area, it is important to ensure that DA boundaries are accurate in reflecting the actual parcel of land. If the DA does not accurately reflect the actual parcel of land, it will not be appropriate to use this level of geography for measuring population density, to which census tracts should be used instead.³
• There may be a critical threshold before density has any impact on active transportation.  One study suggests that “synergistic effects start to occur at 13 residents per acre – transit becomes more viable, driving becomes more expensive, and there are more destinations within walking and cycling distance.⁴
• Density may serve as a proxy indicator for level of transit service or demographic characteristics or ease of car use; ultimately, density may not have a significant independent effect.^2,4
• Due to conflicting evidence between density, and travel behaviour and patterns,  increasing density alone should not be the sole factor aimed at increasing physical activity and/or mitigating the rise in obesity.^2,4,5
• Although, many studies have found a strong positive correlation between density and the decision to walk, cycle or take transit, other studies have found conflicting evidence. For example, some studies found that when residential and retail density was high, there was an increase in the percentage of people walking to work or shopping. However, other studies did not find this correlation.^4,5
• Potential uses of population density indicator are:
• Design of household surveys, for example, when designing a stratified cluster survey, stratification by population density and with probability of selection proportional to population is often used.
• Emergency planning, for example, population density is widely used in the emergency planning for potential disasters such as nuclear reactor accidents or in the estimation of emergency care demand across regions.
• Environmental exposure assessment, for example, population density is often used as an independent variable in the models to predict spatial variability of air pollutants.
  

Definitions

• Urban area: Area with a population of at least 1,000 and no fewer than 400 people per square kilometre.⁶
• Rural area: All territories outside urban areas is classified as rural.⁶

Cross-References to Other Indicators

• Job Density (Section 2C: Built Environment and Health)
• Land Use Mix (Section 2C: Built Environment and Health)
• Proximity to Community Focal Point (Section 2C: Built Environment and Health)
• Population by Age and Sex (Section 1: Population)
• Population Growth (Section 1: Population)
• Projected Population Growth (Section 1: Population)
• Dependency Ratios (Section 1: Population)
• Urban and Rural Population (Section 1: Population)
• Aboriginal Population (Section 1: Population)
• Immigrant Population (Section 1: Population)
• Ethnic/Cultural Origin (Section 1: Population)
• Mother Tongue (Section 1: Population)
• Home Language (Section 1: Population)
• Percent Who Cannot Speak English nor French (Section 1: Population)