Microcomputer revolution --> new uses for census data, specifically microdata Effective use or...

Census 2000 symposium, session 4 paper 26

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Archiving Census Archiving Census Documentation and Microdata:Documentation and Microdata:

Preserving Memory, Preserving Memory, Increasing StakeholdersIncreasing Stakeholders

* * ** * *Wendy L. Thomas and Robert Wendy L. Thomas and Robert

McCaaMcCaaMinnesota Population CenterMinnesota Population Center

http://www.ipums.org/Internationalhttp://www.ipums.org/InternationalIPUMS International, funded byIPUMS International, funded by

The National Science Foundation of the United The National Science Foundation of the United StatesStates


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» Microcomputer revolution --> new uses for Microcomputer revolution --> new uses for census data, specifically microdatacensus data, specifically microdata

» Effective use or microdata requires Effective use or microdata requires systematic preservation of metadata systematic preservation of metadata

» Availability of microdata --> enhances the Availability of microdata --> enhances the value of censuses and increases value of censuses and increases stakeholdersstakeholders

» IPUMS International consortium promotes IPUMS International consortium promotes preservation and use of census microdatapreservation and use of census microdata

Subtext: Subtext: Preserving census metadata and Preserving census metadata and

microdatamicrodataenhances value of census enhances value of census

and increases stakeholdersand increases stakeholders


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16th century Aztec census 16th century Aztec census (in Nahuatl, (in Nahuatl, 1530s1530s): “Here is the ): “Here is the

home of...”home of...”

translatranslatedted

(from Museum of Antropology, (from Museum of Antropology, Mexico City)Mexico City) original original

ms.ms.

digitizdigitizeded

transcritranscribedbed


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121001026007007200000112100001042220020260070072000001121000010432300100600700720000012123000000423002004007000000000000000000005230020020070000000000000000000062300200000700000000000000000000

Census microdata Census microdata of the 21st (and late 20th) of the 21st (and late 20th)

century: century: Who will preserve them?Who will preserve them?

Will they be made usable?Will they be made usable?

Census Census microdata:microdata:

Public goods should Public goods should be usedbe used

Censuses are Censuses are costlycostly

Where microdata are available, Where microdata are available, they are usedthey are used


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……official statistics that meet the official statistics that meet the test of practical utility are to be test of practical utility are to be compiled and made available on compiled and made available on

an impartial basis by official an impartial basis by official statistical agencies to honor statistical agencies to honor

citizens’ entitlement to public citizens’ entitlement to public information.information.

-- UN Statistical Commission, -- UN Statistical Commission, 19941994


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How anonymized census samples How anonymized census samples became a standard statistical became a standard statistical

product:product:» USA: 1960, 1970, 1980, 1990: varying densities; USA: 1960, 1970, 1980, 1990: varying densities;

gaining on CPS as most widely used demographic gaining on CPS as most widely used demographic microdatamicrodata

» Canada:Canada:- 1971, 1976, 1981, 1986, 1991, 1996: varying - 1971, 1976, 1981, 1986, 1991, 1996: varying

designsdesigns- 1996: Data Liberation Initiative led to an - 1996: Data Liberation Initiative led to an

explosion in of usage in research and teachingexplosion in of usage in research and teaching» UK: UK:

- 1991: 2% individuals, 0.5% households- 1991: 2% individuals, 0.5% householdshundreds of publications, thousands of users hundreds of publications, thousands of users

- 2001: double the densities.- 2001: double the densities.


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IPUMSIPUMSii helps five ways: helps five ways: » 1. 1. InventoryInventory the world’s census microdata the world’s census microdata» 2. 2. PreservePreserve endangered microdata and endangered microdata and

documentationdocumentation* * ** * *

» 3. 3. AnonymizeAnonymize census microdata to preserve census microdata to preserve statistical confidentiality, using highest standards statistical confidentiality, using highest standards (Stat. Nether.)(Stat. Nether.)

» 4. 4. IntegrateIntegrate datasets of selected countries using datasets of selected countries using UN, Eurostat and other standardsUN, Eurostat and other standards

» 5. 5. DisseminateDisseminate database free with complete copies database free with complete copies to all partnersto all partners

IIntegrated ntegrated PPublic ublic UUse se MMicrodata icrodata SSeries - eries - IInternationalnternational


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PPAAYYSS

IIPPUUMMSSii

» Assemble microdata and Assemble microdata and documentationdocumentation

» Develop samples to minimize Develop samples to minimize confidentiality risks and maximize confidentiality risks and maximize robustnessrobustness

» Design national integration planDesign national integration plancensus-by-censuscensus-by-censusconcept-by-conceptconcept-by-conceptcode-by-codecode-by-code

» Write integrated documentation Write integrated documentation

National experts in each National experts in each country are contracted country are contracted

to:to:


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» Microdata...for any population Microdata...for any population or administrative division: or administrative division: Nation, province, district, city, Nation, province, district, city, ethnic group, etc.ethnic group, etc.

» Example: Latin America, Example: Latin America, - 20 countries- 20 countries- 67 censuses inventoried- 67 censuses inventoried- 1% - 100% sample densities- 1% - 100% sample densities- 100,000 to 150 million cases- 100,000 to 150 million cases19th century19th century: : 2 censuses 2 censuses1960s1960s:: 1414 1970s1970s::17171980s1980s:: 1616 1990s1990s::1717

» Found: complete census data for Found: complete census data for Colombia 1973 and 16 other countriesColombia 1973 and 16 other countries

IIPPUUMMSSii

IINNVVEENNTTOORRIIEESS


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PPRREESSEERRVVEESS

UN Demographic Center for Latin UN Demographic Center for Latin America America

(CELADE, Santiago, Chile)(CELADE, Santiago, Chile)~3000 microdata tapes to be ~3000 microdata tapes to be

preservedpreserved

IIPPUUMMSSii

and metadata (documentation)and metadata (documentation)


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Preserve against accident, Preserve against accident, deterioration and technological deterioration and technological

obsolescenceobsolescence» Microdata:Microdata:

- transfer to stable media- transfer to stable media- use standard data storage protocols- use standard data storage protocols- entrust copies with at least two depositories - entrust copies with at least two depositories

» Metadata: collect, catalogue, and reproduceMetadata: collect, catalogue, and reproduce- Enumeration forms (preserve all versions - Enumeration forms (preserve all versions

used)used)- Enumerator and data processing instructions - Enumerator and data processing instructions - Codebooks (photocopies and scanned images)- Codebooks (photocopies and scanned images)- Technical studies, evaluations, reports- Technical studies, evaluations, reports

UN Stat. Div.: entire archive to be UN Stat. Div.: entire archive to be preserved, cataloguedpreserved, catalogued


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AANNOONNYYMMIIZZEESS

IIPPUUMMSSii

Using the highest Using the highest standards currently standards currently

available:available:technical (Eurostat technical (Eurostat

workshops)workshops)administrative (license administrative (license

agreement)agreement)

Imagine a new statistical Imagine a new statistical product: product: a scientifically anonymized a scientifically anonymized census microdata sample made census microdata sample made up of unidentifiable individuals...up of unidentifiable individuals...


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Anonymized census microdata Anonymized census microdata samplessamples

available for European countriesavailable for European countries(* = in IPUMS(* = in IPUMSii consortium, consortium, * * = =

negotiating)negotiating)» 16 countries available via PAU, 1990 round 16 countries available via PAU, 1990 round (3 in IPUMS(3 in IPUMSii, 4 negotiating):, 4 negotiating):» Belgium, Czech Republic, Estonia, Belgium, Czech Republic, Estonia,

**Finland, *Hungary, Finland, *Hungary, **Italy, Latvia, Italy, Latvia, Lithuania, Lithuania, **Norway, Poland, *Spain, Norway, Poland, *Spain, Sweden, Switzerland, Sweden, Switzerland, **Russia, Turkey, *UKRussia, Turkey, *UK

» 11 countries not available via PAU (2 in 11 countries not available via PAU (2 in IPUMSIPUMSii):):» *Austria, Croatia, Denmark, *France, *Austria, Croatia, Denmark, *France,

Germany, Iceland, Ireland, Germany, Iceland, Ireland, **Netherlands, Netherlands, Portugal, Slovak Republic, SloveniaPortugal, Slovak Republic, Slovenia


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International Monetary Fund’s International Monetary Fund’s General Data Dissemination General Data Dissemination

SystemSystem52 countries with uniform 52 countries with uniform

standardsstandards» All embrace strict standards of statistical All embrace strict standards of statistical

confidentialityconfidentiality» Prohibit disclosure of information which Prohibit disclosure of information which

may identify individuals or entitiesmay identify individuals or entities» 37 of 52 countries distribute anonymized 37 of 52 countries distribute anonymized

census microdata samplescensus microdata samples» Microdata samples are becoming standard Microdata samples are becoming standard

statistical products statistical products


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IINNTTEEGGRRAATTEESS

Photos from Colombia Photos from Colombia integration projectintegration project, February, February--

March, 2000:March, 2000:4 experts from DANE (census 4 experts from DANE (census

office)office)+7 academics (3 universities)+7 academics (3 universities)

IIPPUUMMSSii

Standard:UN/Standard:UN/Eurostat Eurostat Principles & Principles & Recs...Recs...

Census Census documentation documentation compiled for compiled for Colombian Colombian microdatamicrodata


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DDIISSSSEEMMIINNAATTEESS

IIPPUUMMSSii

» End-User license agreement End-User license agreement » protects privacy and confidentialityprotects privacy and confidentiality» assures proper use assures proper use

» User selects User selects » countries, countries, » cases, cases, » variables, and variables, and » samples--makes chronological &/or samples--makes chronological &/or

cross-national research possible cross-national research possible using census microdatausing census microdata

» Open architecture software and Open architecture software and mirror sites available to all mirror sites available to all partnerspartners

International web-based International web-based access system access system


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153 countries with 1 million + pop. in 2000153 countries with 1 million + pop. in 20002000 round figures are provisional2000 round figures are provisional

Population censuses became Population censuses became universal in the 20th century. universal in the 20th century.

Will census microdata ... in Will census microdata ... in the 21st?the 21st?


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additional information at:additional information at:http://www.ipums.org/internatihttp://www.ipums.org/internati

onalonal

* * * * * ** * * * * *

Thank youThank you


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Preserving Memory, Increasing Preserving Memory, Increasing StakeholdersStakeholders

» 1. Introduction: Well-preserved documentation 1. Introduction: Well-preserved documentation and data -->effective data collection, and data -->effective data collection, dissemination, usedissemination, use

» 2. Long-term preservation of documentation and 2. Long-term preservation of documentation and datadata

» 3. Determining What to Preserve3. Determining What to Preserve» 4. Assessing Future Value4. Assessing Future Value» 5. Inventory of available technology/ personnel/ 5. Inventory of available technology/ personnel/

knowledgeknowledge» 6. Conclusion: Preserve and make accessible 6. Conclusion: Preserve and make accessible

census microdata to enhance value of census census microdata to enhance value of census (IPUMS(IPUMSi i ))

Microcomputer revolution --> new uses for census data, specifically microdata Effective use or...

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