Small Area Statistics

Small Area Statistics

Standard Census Geography and Navigating High-Demand 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

Small Area StatisticsObjectives 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, DLI!

No need to label the areas: the image says enough

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

The Statistics Canada 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

(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 applied to statistics

• 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

Roads and their attributes

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