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Standard Census Geography and Small Area Statistics. Objectives today - to build understanding of: The standard of terminology and hierarchical structure of Census geography, to understand commonly accessible smaller units
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Objectives today - to build understanding of: The standard of terminology and hierarchical structure of Census geography, to understand commonly accessible smaller units Other small geographical units important to statistical display which are important/frequently requested Key Statistics Canada tools to understand their geographic standard, and find small-area standard statistics Standard Census Geography and Small Area Statistics
Geography and Statistics: the ‘Where” Statistics always have a ‘where’ The importance of the ‘where’ varies depending on what you’re examining
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Geography and Statistics: the ‘Where” • Geographic standards are a key method by which disseminated statistics are organized • ‘Where’ statistics – when the ‘where’ question is a ‘small area’ – present unique challenges
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A brief hierarchy overview All levels of the hierarchy have definitions and corresponding codes Eg. Canada – 00; Alberta (Province) – 48 The levels and codes have defined relationships Below provinces, we have Census Divisions: eg 4801 Below provinces, Census Metropolitan Areas and Census Subdivisions Below those, Census Tracts and Dissemination Areas (StatsCan’s SMALL AREA STATISTICS)
The Census Geography Hierarchy Organizing a national system of statistical reporting depends on a full-coverage nested geographic hierarchy The hierarchy helps to ensure 100% coverage of the population during Census collection by organizing the country’s geography
Building a Census Subdivision Code • Province (Alberta) • 48 • Census Division (Census Division 11) • 4811 • Census Subdivision (Census Subdivision 061) • 4811061 • 4811061 = Edmonton
Census division (CD) Group of neighbouring municipalities joined together for the purposes of regional planning and managing common services.
Census Consolidated Subdivision (CCS) A group of adjacent Census Subdivisions. Smaller, more densely-populated Census Subdivisions (towns & villages) are combined with the surrounding, larger, more rural Census Subdivision, in order to create a geographic level between the Census Subdivision and the Census Division. CCS - Leduc County 4811012
CCS - Leduc County 4811012 2011 Census of Agriculture
1931 1921 1911 Historical Census Sub-Divisions Alberta Total Population 1951 1941
The Census Geography Hierarchy • The hierarchy also defines ‘level’ of the release of statistics • Small area statistics exist at the ‘bottom’ (yet $$) end of the hierarchy
Expense and access Authoring agencies, because of budget limitations, sometimes have to strike balance between availability of variable detail and finer levels of geography
Expense and Access More variables? > $$$ Smaller geography? > $$$ !! Thanks Data Liberation Initiative! Thanks, Open Data movement! Thanks, new discovery tools!
Great StatsCanGeography Tool for understanding the hierarchy Illustrated Glossary Overview Tutorial: http://www.statcan.gc.ca/pub/92-195-x/92-195-x2011001-eng.htm Well-defined geographic areas provide the framework for the collection, presentation and analysis of data.
Census metropolitan area (CMA) 48835 Edmonton must have a total population of at least 100,000 of which 50,000 or more live in the core
Building a Census Tract Code • Census Metropolitan Area (Edmonton – 835) • 835 • Census Tract (Census Tract Name = 061) • 8350061.00 • 8350026.02 = ?
Census Tract Lookup – 2011 Census • http://www12.statcan.gc.ca/census-recensement/2011/dp-pd/prof/index.cfm?Lang=E
Dissemination Area (DA) Small area composed of one or more neighbouring dissemination blocks, with a population of 400 to 700 persons. All of Canada is divided into dissemination areas. 2011 Census Tracts (CT) 2011 Dissemination Area s (DA)
Hierarchy continued Hierarchy is defined administratively (ie political decision) and statistically (ie StatsCan’s reporting requirements) Not everything in the hierarchy relates to every other unit (see chart); i.e. not a straight, linear hierarchy Eg. Forward Sortation Areas Odd units: ‘Designated Places’
Hierarchy Caveats Not all statistics are available for all levels of the hierarchy; parts of the hierarchy may not exist in some places Statistical analysis is more appropriately applied to some units than to others: eg. CMA vs CSD
Privacy and confidentiality Keeping the unit of analysis anonymous is a challenge with small area information (if one has good local knowledge, you can identify a person) There are rules in place about what population counts are required in order for small area statistics to be released (e.g. income)
Small Area Statistics: A context for understanding geographic standards Small area statistics: Help us understand the broader geographic standard of stats dissemination from Statistics Canada Are essential for certain types of analyses Can be challenging to find, understand and to work with; Can answer local and very specific questions Can be expensive to produce and obtain (i.e. present access challenges)
What are ‘small area statistics’ about? High demand for information at the ‘lowest geographic level available’ Statistics at sub-provincial, or sub-municipality level, are critical to analyses of: Health (e.g. spread of disease), Housing, crime, social issues (e.g. emerging patterns of concern or interest), Emergency response (analysis of this doesn’t work at a whole-municipality level), Market analysis (often derived from postal code geography) Municipal planning
John Snow’s Cholera Outbreak Map Street map of cholera deaths in Soho in 1853 from John Snow's On the Mode of Communication of Cholera
This is a map of every person counted by the 2010 US, 2011 Canadian, and 2010 Mexican censuses. The map has 454,064,098 dots - one for each person. http://www.theatlanticcities.com/design/2012/12/mapping-census-dot-every-person/4273/
Edmonton – Calgary Corridor Census Dotmap ArcGIS – 2011 DA - Total Population CCS - Population 1 Dot = 1 Person
Geographic Standard and Small Area Statistics What are the important small area statistics in the standard hierarchy? Most commonly: Census Tracts and Dissemination Areas
Other small-area data units What do our patrons want geographically that does not conform to the StatsCan geographic standard? Data typically compiled into statistics to meet the needs of the authoring organization Who ELSE cares about these areas/what demands are in place for this information? Solutions are available!
Neighbourhoods Frequent need for statistics at this level of geography Census tracts vs. neighbourhoods Municipalities: purchasing profiles and sharing agreements
Edmonton 2012 Census https://data.edmonton.ca/browse?category=Demographics&q=census&sortBy=relevance&tags=2012+municipal+census
Postal Codes Frequently requested for market analysis/business applications Represented graphically by dots in a product called the Postal Code Conversion File (PCCF) - Postal codes are regions! The PCCF allows matching of postal codes to the best corresponding dissemination area – Has not been released for the 2011 Census**
1911 Micro Census - Alberta http://ccri.library.ualberta.ca/en1911census/codes/index.html Fire Insurance Plans – Edmonton 1913 1911 Census