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Understanding Historical Canadian Census Data Changes

Explore the evolution of Canadian census data collection, coding, and geography from 1911 to 2006, highlighting shifts in variables and units of observation.

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Understanding Historical Canadian Census Data Changes

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  1. Chasing Chilliwack: recent historical Canadian census aggregate statistics[version 2] A workshop at ACCOLEDS 2008 Laine Ruus <laine.ruus@utoronto.ca> 2008-12-02

  2. Outline • Introduction • What’s changed about census, and when did it change • Following a geographic area over time

  3. How Chilliwack grew Sources:http://www.chass.utoronto.ca/datalib/misc/accoleds/2008/accoleds08_resources.htm#fn1

  4. Introduction • Study of change over time is increasingly interesting, as data time-lines get longer • Most pre-1961 census products are print-only • STC began to make extensive use of computer equipment with the 1951 census; computer-readable aggregate statistics beginning in 1961 • CCRI has a project to produce microdata from 1911-1951 census, as well as some aggregate products

  5. Introduction (cont’d) Working with historical census aggregate data involves dealing with: • Changes to variable collection, coding, and definitions • Changes to units of observation • Changes to census geography • Changes to file organization • Changes to census products

  6. Changes to variable collection, coding, and definitions • Compare the definition of ethnic origin in 1981 (p.14 in): http://prod.library.utoronto.ca:8090/datalib/codebooks/c/cc81/dict81.pdf • With those in 2006: http://www12.statcan.ca/english/census06/reference/dictionary/pop030a.cfmand http://www12.statcan.ca/english/census06/reference/reportsandguides/ethnic-origin.cfm

  7. How a variable is collected is one thing, how it is coded is another… • 1981 ethnic origin : • EA-level: profile & BST (12) • CT-level: profile (5); BST (42) • CSD-level: profile (5); BST (12, 42) • 1991 ethnic origin : • EA-level: profile (35); BST (25) • CT-level: profile (35 ); BST (25) • CSD-level: profile (35); BST (25) • 2001 ethnic origin : • DA/CT/CSD level: profile (61); BST (na) [BST=basic summary tabulation]

  8. Changes to unit of observation • Now 5 basic units of observation: individual, census family, economic family, household, dwelling • 1871 – individual • 1921 – ‘census family’ versus ‘private family’ • 1931 – ‘private family’ became ‘household’ • 1956 – ‘economic family’ introduced • Note:always use the appropriate denominator – short form population for short form variables, long form population for long form variables!

  9. Census products by geographic area and medium • Enumeration areas: 1961-1996 • Computer-readable only, never available in print • Dissemination areas: 2001-2006 • Computer-readable only, never available in print • Census tract: • Print/microfiche: 1951-2006 • Computer-readable: 1971-2006 • Provincial census tracts • Print: 1981 • Computer-readable: 1971-1981

  10. Census products by geographic area and medium (cont’d) • Census subdivision (municipalities) level • Print: 1851-2006 • Computer-readable: 1971-2006 • Census division (counties) level • Print: 1851-2006 • Computer-readable: 1971-2006 • CMA/CA • Print: 1936/1941-2006 • Computer-readable: 1971-2006

  11. Census products by geographic area and medium (cont’d) • Federal electoral district level • Print: 1851-2001 • Computer-readable: 1971-2006 • Forward sortation area level • Never in print • Computer-readable: 1986-2006 • Province level • Print: 1840-2006 • Computer-readable: 1971-2006

  12. Brief guide to census geography: what changes and why • Enumeration areas were the basic building block • Did not cross other STC boundaries • Therefore could be added up to all higher levels of geography • Physical area covered by one enumerator • Assigned numeric code: prov(2)+fed(3)+ea(3) • Not geographically stable (ie could and did change with each census/stack on top of each other, etc

  13. Brief guide to census geography: what changes and why (cont’d) • Dissemination areas introduced in 2001 • DAs replace EAs as smallest geographic area for which census data are released • DAs respect CTs, CSDs, and by extension, CD boundaries • Assigned numeric code: prov(2)+cd(2)+da(4) • Planned to be geographically stable • Comprised of Dissemination Blocks (DBs), the new basic building block • No standard data products except population and dwelling counts at DB level

  14. Changes to census geography (cont’d) • Census tracts • first defined in 1941 census, as ‘social areas’ • renamed census tracts (1951) • major reorganization of census tract boundaries and names in 1971 • assigned numeric code: cma(3)+ctcode(4) and numeric ‘name’ (cma(3)+ctname(7.2) • split when they grow too big (and STC has the budget to split them) • when they split, ‘root’ remains the same, ie 7.00 becomes 7.01 and 7.02

  15. Changes to census geography (cont’d) • Area aggregates/Provincial census tracts • Created in 1971, as ‘area aggregates’ • 1976 became provincial census tracts • covered all Canada outside census-tracted urban areas • only available in BCTs, in 1971 • 1981 included in BCTs and print profile • assigned a numeric code: prov(2)+pctcode (4) • disappeared in 1986 census products

  16. Changes to census geography (cont’d) • Census subdivisions (municipalities) • Defined Municipality Acts of by provincial/territorial governments, + unincorporated areas • Named areas, but assigned numeric code: prov(2)+cd(2)+csd(3) • See: • Standard geographical classifications (1974-2008) • Interim list of changes to municipal boundaries, status, and names http://www.chass.utoronto.ca/datalib/codebooks/cstdli/92f0009xpb.htm

  17. Changes to census geography (cont’d) • Indian reserves • Indian reserves defined by IAND • 1961 Indian reserves lumped together in each county • 1971 Indian reserves lumped together in each census subdivision (municipality) • 1981 Indian reserves became discrete census subdivisions

  18. Changes to census geography (cont’d) • Census divisions/counties, etc. • defined by provincial legislation (in some provinces only), or by Statistics Canada • Name and assigned numeric code: prov(2)+cd(2) • Census metropolitan areas/census agglomerations • Defined by urban core plus ‘labour watershed’ (STC defined) • Aggregations of complete CSDs • Name and assigned numeric code: cma(3)

  19. Changes to census geography (cont’d) • Federal electoral districts • Defined by federal Electoral Boundary Readjustment Acts, about every 10 years. • Name and numeric code: prov(2)+fed(3) • Forward sortation areas (FSAs) + Local delivery units (LDU) • Defined by Canada Post • Do not respect/are not respected by any Statistics Canada geographic areas • 3-6 digit alpha-numeric codes

  20. Adding up census geography • The following table shows which levels of census geography can be added up to which larger levels of census geography • Why you should avoid doing so whenever possible: • Area suppression • Random rounding causes distortion

  21. Adding up levels of census geography: hu=health unit

  22. Four ways to chase census geography over time • Named areas, through Official lists and Geography tape/attribute file/Geosuite • Coded areas, through EA/DA and CT correspondence files • Paper maps where available • Overlaying vector/boundary files, where available

  23. Identifying areas • Larger geographic areas have names, and have been assigned numeric codes • Both codes and names can change • Eg ‘23’=‘’Vancouver’ in 1971; ’933’ = ‘’Vancouver’ post-1971 • Eg ‘Hull’ became ‘Gatineau’ in 2006 • CTs and EAs/DAs have only codes • Ctuid=cma(3)+ctname(7) • Dauid=prov(2)+cd(2)+da(4) • Eauid=prov(2)+fed(3)+ea(3)

  24. Exercise 1: • Is/was Chilliwack, BC a CMA or a CA? • What was Chilliwack’s CMA/CA code in 1971? In 2006? When did it change? • Did Chilliwack have census tracts in 1971? In 2006? • Hint: see table athttp://www.chass.utoronto.ca/datalib/other/referenc.htm#sgc

  25. Chasing named places thru time: • Finding codes of ‘named’ areas over time: • Standard geographical classification (STC 12-554+) 1974-2008 • Geography attribute file/Geography tape file (1971-1996, 2006) • Geosuite/Georef (1996-2006) • Interim list of changes to municipal boundaries, status, and names 1965- . • Place name master file/Locality name file

  26. Interim list of changes...

  27. Place name master file

  28. Exercise 2: What CSDs comprised Chilliwack CA in 1971? • Hint: use Geography tape/attribute files at: http://www.chass.utoronto.ca/datalib/major/sda.htm#agg

  29. You can accomplish much the same with the Geography tape files in SPSS, with the following syntax:

  30. Chasing coded places thru time: • Enumeration/dissemination area correspondence files • available 1971/76 to present • Census tract correspondence files • Available for 1991-1996, 1996-2001, 2001-2006 • Prior years in print in census tract profile volumes • UT/DLS has created files of 1966-1971 to 1987-1991 <http://www.chass.utoronto.ca/datalib/major/georef.htm> • These resources indicate only whether or not there has been a change, not how much

  31. Exercise 3: • What enumeration areas comprised Chilliwack CA?

  32. Exercise 4: • Calculate the %British ethnic origin in Chilliwack CA in 1981, in 2006?

  33. The manual chase • Need print maps of the areas at each census • A list of print map resources at UT is at: http://www.chass.utoronto.ca/datalib/major/prmapag.htm • Alternatively, use the Official lists (1961-1981), and Geosuite (1996- ) • Note: Official lists are difficult to track down from some censuses, as these were not official publications with DBS/STC catalogue numbers

  34. Overlay vector files • Need vector files for each census. A list of files available at UT, see: http://www.chass.utoronto.ca/datalib/major/spmapagg.htm • Requires appropriate GIS software

  35. Exercise 5: Using the CHASS analyzer interface at: http://dc2.chass.utoronto.ca/census/1981/ save all 2006 Chilliwack census tracts, for the following variables: British ethnic origin, the appropriate population total, in .dbf format.

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