IPUMS workshop * * * Robert McCaa, Professor of Population History University of Minnesota additional information at:

The IPUMS team (lack computer gurus, some researchers, & 3 PIs were away or too busy to pose!) Steven Ruggles, Inventor of IPUMS, Professor of History and Director, Minnesota Population Center

IPUMS-Greece Timeline May, 2003: Memorandum of Understanding signedMay, 2003: Memorandum of Understanding signed July, 2005: Microdata samples entrusted for censuses of 1971, 1981, 1991 and 2001July, 2005: Microdata samples entrusted for censuses of 1971, 1981, 1991 and 2001 April, 2006: Translations of documentation completedApril, 2006: Translations of documentation completed Dec., 2006: Integration completed; dissemination beginsDec., 2006: Integration completed; dissemination begins

Outline (65 slides, yikes!!) » 1. IPUMS goals and milestones 11 slides » 2. Applying for Access8 slides » 3. Studying documentation 15 slides » 4. Creating an extract9 slides » a. Selecting samples » b. Selecting variables » c. Selecting sub-populations » 5. Integrating microdata9 slides » 6. Managing access: Users and Uses 13 slides

Project goals IPUMS is a global partnership to (1) preserve census microdata and documentation, (2) integrate census microdata samples, and (3) manage access to anonymized sample extracts for researchers and policy makers, at no cost—regardless of country of birth, residence or citizenshipIPUMS is a global partnership to (1) preserve census microdata and documentation, (2) integrate census microdata samples, and (3) manage access to anonymized sample extracts for researchers and policy makers, at no cost—regardless of country of birth, residence or citizenship

Preservation: 1973 census tapes of Sudan at risk!

A Solution: Data recovery

Data recovery. Example: Bangladesh Bureau of Statistics (1981 census, 276 tapes to recover) >3,000 tapes recovered: 1971 Germany 1980 Mexico, Mali 76, Sudan 73 and many more Microdata on this tape were recovered!!

Integration, Dissemination: March 2008 dark green = disseminating (26 countries, 80 censuses, 200mpr) green = harmonizing (34 countries, 95 censuses, 190mpr) lightest green = negotiating (see handout) Mollweide projection

Milestones » 1999: Founded by Steven Ruggles and Bob McCaa, –restrict access to trusted users, and apply corresponding confidentiality techniques » 2002: 1 st release of integrated samples for 7 countries; >200 users in first year » 2008: Big hit! 79 countries signed; 70 entrusted data to IPUMS, datasets for more than 230 censuses, >150 entire datasets

Milestones » 2007, 4 th release: » data for 26 countries, samples for 80 censuses, » 202 million person records, » ~2,000 users » 2009, 6 th release: » data for 40 countries, samples for ~130 censuses » >300 million person records » thousands of users » Note: data extracts are provided only to licensed users.

2. Using 1. Logon w/ password 2a. Study documentation 2b. Design extract 3. Receive ; logon with p/word 4. Download extract (SSL encrypted) 5. UnZip data (also SAS, STATA) 6. Analyze

- Warning - IPUMS microdata are anonymized samples.IPUMS microdata are anonymized samples. –They are for advanced analysis and research. –Use of a statistical software is required. – Statistical software provides great power. – “With great power, comes great responsibility.” IPUMS samples are for analysis.IPUMS samples are for analysis. IPUMS samples are not official statistics.IPUMS samples are not official statistics.

Apply for access (see form and conditions of use) Study integrated documentation (variables) Link to Official Statistical Agency home pages Examine integrated metadata (samples) Construct a custom-tailored request: select countries, years, sub-populations, & variables

1. Respect “restricted-access” conditions of use: protect confidentiality; “share” data with only with registered users 2. Study both source documentation and metadata: » source: census forms and instructions to enumerators » metadata: samples, variables, comparability discussions 3. Construct extracts judiciously: use “subsamp” (1% sample for testing) extract only needed countries, censuses, variables, sub-pops 4. Use weights: either households or individuals (geographical strata = power) 5. Analyze carefully: proper statistical techniques, keeping in mind data quality 6. Cite properly: IPUMS i and National Statistical Agencies 7. Share publications: IPUMS i and National Statistical Agencies Dr. Bob’s 7 rules for using IPUMS i microdata