Household Surveys ACS – CPS - AHS

1. Household SurveysACS – CPS - AHS INFO 7470 / ECON 8500 Warren A. Brown University of Georgia February 22, 2011

6. CES Discussion Papers

11. Purpose Target Population Sampling Frame Data Collection Non-Response Missing Data Weighting Sampling Error PUF / IUF Data Access to Reports Research Questions Resources Outline

12. American Community Survey Sponsor: Census Bureau Collector: Census Bureau Purpose: “The American Community Survey (ACS) is an ongoing survey that provides data every year -- giving communities the current information they need to plan investments and services. Information from the survey generates data that help determine how more than $400 billion in federal and state funds are distributed each year.”

13. ACS: Purpose • Key Component for Re-Engineered Census • Replacing the Decennial Census “Long-Form” • Continuous measurement rather than snapshot • Meet federal legislative and program needs • Other stakeholders in state and local government and private sectors • Provide annual data on demographic, social, economic and housing characteristics. • Improve the Federal Statistical System

14. Advantages of the ACS • Timeliness • Comparability • Reliability • Numerous data products

15. ACS: Target Population • Current residence not “Usual Residence” • “two-month rule” • Household population in 2005 • Total (HH + GQ) in 2006 and …. • GQ residency is “de facto”

16. ACS: Sampling Frame • Master Address File (MAF) • Official inventory of known living quarters • Linked to TIGER • Housing Units • Based on Census 2000 MAF and updates from the USPS’ Delivery Sequence File • Group Quarters • … and updates from the administrative records and the FSCPE • Excluded from ACS are domestic violence shelters, soup kitchens, commercial maritime vessels,…

17. ACS: Design of the Sample • Annual Sample Size of 3 million addresses • Series of Monthly Samples of 250,000 addresses • HU sample in each of the 3,141 Counties • Areas with smaller populations sampled at higher rates than those with larger populations • HU Address sampling rate set by Block based on entity (municipality, school district, tract) • Final sampling rate varies between 1.6% and 10% • No HU address can be sampled more than once in 5 years

18. ACS: Questionnaire • Content designed to meet the needs of federal government agencies • 21 housing and 48 population questions • Household Respondent provides responses for all other residents of the household • Householder or Reference Person is “Person 1”

19. ACS: Data Collection • HU addresses by three modes • Mailout of paper questionnaire in 1st month • Telephone (CATI) non-response follow-up in 2nd month • Personal visit (CAPI) non-response follow-up in 3rd month to a sub-sample • GQ • Personal visit within 6 weeks of sample selection

20. Data Collection Timetable

21. Non-Response Follow Up • 1st Month – Mailed Questionnaire • 2nd Month – Attempt at Telephone Interview • 3rd Month – Sub-Sample of Non-Respondents • 67% unmailable addresses • 50% low response tracts • 33% high response tracts

22. ACS: Response Rates • Participation is mandatory • Sample addresses eligible for interviewing: • 51% Mail response • 9% CATI non-response follow-up • 38% CAPI non-response follow-up • 2% Non-interview

23. ACS: Missing Data Item non-response or failed edit check • FEFU – failed-edit follow-up • More than 5 household members • Critical questions not answered • 33% of mail return questionnaires in 2005 • Imputation • Assignment used other data on respondent • Allocation – hot deck procedure • Flags variables

24. ACS: Weighting • Person and Housing Unit weights • Three stages • Probability of selection (initial sampling rate) • Adjust for non-response • Control to Population Estimates • Sum the weights • Person weights for person characteristics • HU weights for family, household or housing unit characteristics • Householders = Households ???

25. ACS: Weighty Issues ACS 2005 for United States • 288,378,137 Persons in Households • 111,090,617 Households • 114,763,475 Householders • Average Household Size • 2.60 based on Households • 2.51 based on Householders

26. ACS: Sampling Error • Publishing margins of error in tables • More sample less error • 1, 3, and 5 year estimates and associated sampling error • Sampling error for small area data is proving to be a problem

27. Complex Sample Surveys and Weights • Weight - numeric variable expressing the number of housing units or people that an individual microdata record represents • Sum of the housing unit and person weights for a geographic area is equal to the estimate of the total number of housing units and people in that area • Values for weights vary • Different Probability of Selection • Differential Response Rate • Control to Population Estimates

28. Alternatives for Estimating Standard Error • Design Factor • Replicate Weights • Ignore

29. Alternatives for Estimating Standard Error • Design Factor • Design factors are factors to multiply times the standard error of a simple random sample. • Easier to use than the replicate weights • Replicate Weights • Generally, more accurate • Somewhat more work than design factors

30. Estimate of Sampling Error Using Design Factors

31. Design Factors * West Virginia is 1.0 for Age and 1.5 for Person Income

32. Estimate of Standard Error Using Replicate Weights where: • X is the estimate formed from the PUMS weight • Xr is the estimate formed from the rth replicate weight.

33. PUF / IUF • 1% Sample • PUMA • Top Coding • Collapsed Categories • Perturbation • No Administrative • 2.5% Sample • Block/Tract/Place • Full Distribution • Full Distribution • Actual Ages • Details of Collection

35. ACS: Research Questions

36. Resources • Census Bureau • IPUMS • Michigan Population Studies Center • National Academy Sciences-CNSTAT

37. ACS on www.census.gov

41. http://www.psc.isr.umich.edu/dis/acs/dataanalysis/UsingReplicateWeights.htmlhttp://www.psc.isr.umich.edu/dis/acs/dataanalysis/UsingReplicateWeights.html

42. NAS-CNSTAT ACS Reports *********** 2001, CNSTAT’s 2007, Census 2008, core sponsors Bureau NSF/SRS