1. Using IPUMS.org Katie Genadek Minnesota Population Center University of Minnesota kgenadek@umn.edu The IPUMS projects are funded by the National Science Foundation and the National Institutes of Health 00:00

2. Overview What is IPUMS? Microdata and Summary Data IPUMS-USA IPUMS-CPS Online Analysis System Online Demonstration Questions 00:44

3. What is IPUMS? Integrated - consistent codes, labels, and documentation Public Use - anonymized, downloadable Microdata - individual-level Series - pooled data over time and place 1:26

4. But, What is IPUMS Data? Individual level: Demographic Data Census Data Survey Data Health Data Historical Data Migration Data Time Use Data Summary level: Demographic Data Census Data Historical Data Mapping Data 2:09

5. MPC Data Projects http://www.ipums.org/ 2:41

6. MICRODATA AND SUMMARY DATA Microdata: 4:40

7. Microdata versus Summary Data Shows full range of responses for individuals Enable custom tables and sophisticated analyses Suppression: geography, truncation, and item level suppression Premade or published tables of aggregate characteristics Enable examination of small geographic areas Suppression: limited content, grouped intervals, and cell suppression MicrodataSummary Data 4:40

8. Summary Data 5:44

9. Household record (shaded) followed by a person record for each member of the household Relationship Age Sex Race Birthplace Mother’s birthplace Occupation For each type of record, columns correspond to specific variables IPUMS Data Structure 5:54

10. IPUMS-USA Microdata Data: 6:50

11. IPUMS-USA Database includes public use microdata samples: U.S. decennial censuses (1850-2000) Complete-count dataset for 1880 Linked Samples 1850 – 1930 Samples from Puerto Rico (1910-2008) American Community Survey (2000-2009) The first MPC data project Most widely used database ~ 30,000 users 6:53

12. Census Samples Census Year Sample Density Number of persons in dataset 18501%198,000 18601%354,000 18701%428,000 1880100%50,300,000 19006%5,189,000 19101.4%1,265,000 19201%1,037,000 19305%6,060,000 19401%1,351,000 19501%1,922,000 19601%1,780,000 19706%12,180,000 19809%20,403,000 19906%15,000,000 20006%16,885,000 8:31

13. The American Community Survey Replaced the long form of the Decennial Census –Demonstration stage: 2000 to 2004 –Full implementation 2005, group quarters added 2006 Rolling sample design Microdata samples: Full survey responses for 1% of US population Yearly samples, multi-year samples 9:18

14. ACS Samples Year Sample Density Number of Persons in dataset 20001 in 750372,000 20011 in 2301,200,000 20021 in 2601,075,000 20031 in 2301,200,000 20041 in 2401,194,000 20051 in 1002,878,000 20061 in 1002,970,000 20071 in 1003,100,000 20081 in 1003,001,000 20091 in 1003,030,700 10:03

15. Census and ACS Variable Topics Basic demographic Marriage Family structure Fertility Ethnicity Disability Education Work Income Migration Housing Characteristics 10:13

16. Geography Limitations No confidentiality restrictions for samples prior to 1940 – no geographic limitation Samples from 1940-1970 –Limited and inconsistent geographic identifiers Recent samples: –State –Some Metropolitan Areas –County Groups –Public Use Microdata Areas (PUMAs) 10:43

17. What are PUMAs? Public Use Microdata Areas (PUMAs) Comprised of approximately 100,000 persons Boundaries do not always align with jurisdictional boundaries Detailed contents and maps available GIS shape files for PUMAs available 11:26

18. IPUMS-CPS Microdata Data: 11:53

19. Current Population Survey (CPS) Administered starting 1940 Monthly survey administered by the Bureau of Labor Statistics Household survey was designed to measure unemployment Source of the official Government statistics on employment and unemployment In 2009 - 57,000 households interviewed monthly 11:55

20. Current Population Survey March Supplement All March respondents Additional respondents from February, March and November monthly samples Data are collected for Armed Forces members residing with their families March Annual Social and Economic Supplement is the most widely used by social scientists and policymakers 12:20

21. Current Population Survey March Supplement Labor force participation and unemployment Work experience and educational attainment Sources of income including non-cash benefits Program participation Tax filing status Health Insurance Migration 12:51

22. IPUMS - CPS All March Data (Back to 1962) Basic Monthly Surveys –Samples from 2000-2008 (back to 1976 soon) –Data for every month –~50,000 households surveyed each month –Less variables than March supplement Demographic information Family characteristics Employment status Education information 13:16

23. ONLINE ANALYSIS SYSTEM Obtaining Data: 14:26

24. Online Analysis System High-speed tabulation software developed at UC-Berkeley Allows for analysis of microdata without statistical package All analysis performed online Can analyze multiple years of data Help guides on webpage 14:26

25. Features Data analysis capabilities –Frequencies and cross tabulations (including charts) –Comparisons of means (with complex std errors) –Correlation matrix –Comparisons of correlations –Regression (ordinary least squares) –Logit and probit regression –List values of individual cases 15:02

26. Where is this online tabulator? Follow the link ‘Analyze Data Online’ from the homepage of: –usa.ipums.org/usa/ –cps.ipums.org/cps/ Select all samples of year of interest in USA Open IPUMS-USA or CPS in additional tab for documentation 15:41

27. USE THIS DATA Obtaining Data: 16:00

28. Microdata for Analysis Documentation is Important!!! –Use the IPUMS documentation –Be aware of top/bottom codes, NIU codes, and missing data codes –Know the universe – who got asked the question Weights – makes estimates representative –See additional weights presentation Sample size is important –Check analysis without weights 16:01

29. Microdata for Analysis Allows more complex analysis then summary data Geographic Restrictions –State Level Analysis –Metro Area level Analysis Time series – change over time Not downloading tons of tables 18:43

30. IPUMS is Awesome Comprehensive online documentation Integration makes analyzing change over time possible Data analysis system allows you access the data and analyze it online All of the data are available for free online User support is available by e-mail to help you as needed 19:31

31. Social Explorer - Shout Out Produces online maps and data reports Based on boundary files made available through NHGIS Map changes in census data over time http://www.socialexplorer.com/ 20:23

32. DISCUSSION OF “WEIGHTING” AND ONLINE DEMO OF IPUMS Obtaining Data: 20:54

33. Questions – email us IPUMS User Support ipums@umn.edu Contact: Katie Genadek kgenadek@umn.edu 32:00