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Small Area Statistics. Standard Census Geography and Locating Small-Area Statistics. Geography and Statistics: the ‘Where”. There’s always a ‘where’ The importance of the where varies depending on what you’re examining ‘Where’ is a major way that disseminated statistics are organized
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Small Area Statistics Standard Census Geography and Locating Small-Area Statistics
Geography and Statistics: the ‘Where” • There’s always a ‘where’ • The importance of the where varies depending on what you’re examining • ‘Where’ is a major way that disseminated statistics are organized • ‘Where’ - when it is small - is particularly challenging
Small Area Statistics Objectives today - to build understanding of: • The relationship between geography and statistics • 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 • How to use key Statistics Canada tools to find or review spatial display of small-area standard statistics
Why learn about small area stats? • 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 preparedness (analysis of this doesn’t work at a whole-municipality level), • market analysis, (why do they want my postal code anyway?) • and much, much more!
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, nifty new tools!
The Census Geography Hierarchy • Organizing a national system of statistical reporting depends on a full-coverage nested geographic hierarchy; i.e. geography/GIS for StatsCan is about more than making maps • The hierarchy helps to ensure 100% coverage of the population during Census collection by organizing the country’s geography • The hierarchy also defines ‘level’ of the release of statistics • Small area statistics exist at the ‘bottom’ (yet $$) end of the hierarchy
Great StatsCan Geography Tools for understanding hierarchy • Nice quick tutorial: http://geodepot.statcan.ca/Diss/Reference/Tutorial/HC_tut1_e.cfm • Fantastic glossary: http://geodepot.statcan.ca/Diss/Reference/COGG/Index_e.cfm
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)
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)
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
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 • Ironically, what people want geographically is often not how the data is compiled by Statistics Canada! • 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
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
Exercise: GeoSuite and B2020 for Small-Area Statistics GeoSuite, StatsCan’s Website, and Beyond 20/20 Table link: http://datalib.library.ualberta.ca/data/workshops/CensusAlbertaDA2006.ivt
More exercise Links Start page: • http://www.statcan.gc.ca/start-debut-eng.html Community profiles: http://www12.statcan.ca/census-recensement/2006/dp-pd/prof/92-591/index.cfm?Lang=E
More exercise links Census Data Products: http://www12.statcan.ca/census-recensement/2006/dp-pd/index-eng.cfm Geography Reference Maps: http://www12.statcan.ca/census-recensement/2006/geo/index-eng.cfm