The US Census and Secondary Data Sources

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Secondary Data

Data that someone has collected, collated, or analyzed The US Government provides many secondary data sources

• Environmental Protection Agency• Department of the Interior• Housing and Urban Development• Department of Agriculture• Department of Commerce• Health and Human Services

International agencies• the United Nations• Amnesty International

Secondary Data

Inexpensive – often free Widely available and accessible Thoroughly studied You do not ask the questions or determine the contents

You are never really sure how it is collected

Is an imperfect proxy for what you want to measure

BE CAREFUL 3

CensusHistory

Census mandated in the constitution:

“[An] Enumeration shall be made within three Years after the first Meeting of the Congress of the United States, and within every subsequent Term of ten Years, in such Manner as they shall by Law direct.”

Article 1, Section 24

CensusHistory

Controlling law is Title 13 of the US Code. Title 13 :

determines how often counts are to be made and when they are available (also known as enumeration) is found in 13 USC 141.

sets fines for failure to respond ($100, which was raised from $20 in 1970s). Although this has never been enforced.

mandates a mid-decade census5

CensusHistory – Government Uses

Redistricting—drawing boundaries for Congressional, legislative, etc. districts

Distribution of federal fundsSite locationMarketingProgram needs planningDemographic change research

CensusHistory – Government UsesCensus Is Controversial

It moves power: • Congressional reapportionment• Congressional, state legislative redistricting• redistricting of many elective bodies--city

councils, school boards, etc.

It moves money: • Over 100 federal programs that allocate

$400 billion/year have census counts in some part of formulae

CensusHistory – Census is always changing

Original census counted slaves (“other persons”) as 3/5 of a person. This was changed in the 14th ammendment.

Slavery last asked in 1860

Feeble-minded in 1840-1890

Income first asked in 1940

Televisions surveyed, 1950-70

Detailed ancestry beginning 1980

Multiple races and grandparents as caregivers in 2000

Questions are passed by congress as law8

CensusHistory

Grid of questions available at http://www.lib.umich.edu/govdocs/census2/censubj.pdf

Public health professionals identify vulnerable populations for chronic disease

Urban planners identify zoning, housing, sewage, and transportation issues

Social workers conduct needs assessments for services to the elderly, poor, children

CensusPractical Applications

Marketers target likely buyers

Politicians use the census to determine voting districts and to assess constituent interests

Environmentalists map the spread of toxic effluents and population densities

Occupation by age, race, and sex for equal employment opportunity

Librarians base collection development policy on community characteristics

Mayors use numbers to apply for federal grants. • Undercount costs money – the reason for lawsuits• Racial minorities and undocumented aliens• Should missionaries be counted as U.S. residents

CensusCollection Method - Basic Enumeration

1. Mail Campaign (alerting postcard, the census form, note of thanks).

2. Expect about 60% - 70% response rate

3. Delivered to about 80% of respondants via USPS

4. For most of remaining 20%, census worker left a copy of the census

5. For remaining either used special methods, or collected in person

CensusCollection Method - Basic Enumeration

Service based enumeration – homeless people and people using shelters

Group Quarters enumeration Transient Night (T-Night) enumeration – People living

“mobile lifestyle” (campgrounds at racetracks, public and private campgrounds, fairs and carnivals, marinas)

Remote Alaskan enumeration Domestic military enumeration Overseas enumeration

CensusCollection Method – Nonresponse Followup (NRFU)

1. Sent census workers to collect responses at non-responsding addresses

2. Visited addresses where questions were returned without data

3. Visited buildings that were previously reported as nonexistent or vacant

CensusCollection Method - Undercount

The census cannot count everybody. The difference between the actual number of people

and the number of people the census bureau counts is called the undercount.

There are some people who simply will not answer census questions. Many of whom simply do not trust the enumerators (census workers).

Nonresponders are disproportionately poor and members of a minority group.

The census bureau is trying to estimate the total number through sampling.

CensusCollection Method – Accuracy and Coverage Evaluation (ACE)

1. Create Interactive Coverage Measurement (ICM) a “second” census of 750,000 housing units from around the country

2. Match and compare ICM with enumerated census

3. Make an estimate of undercounts and errors using Dual System Estimation (DSE)

Accuracy and Coverage Evaluation is the Census Bureau’s process for estimating the undercount using sampling methods. There are three basic steps:

2010 Census Changes

• No long form this census (asked for detailed social and economic information)

• Previous long form information will be collected through the American Community Survey on a 1-year or 3-year cycle depending on the size of the community.

2010 American Community Survey Questions

CensusShort Form

Distributed to 100% of households 10 Questions about:

– Age– Sex– Race (Multiple)– Hispanic origin– Household relationship– Owner vs. renter occupied housing

2010 Short Form Questions

2010 State Apportionment

• The first data released from the 2010 Census are the official national and state population counts, which are used to apportion seats in the U.S. House of Representatives.

2010 Census Operational Milestones

• Form delivery and Mail Back Phase (3/1 – 4/16/2010)• Door-to-Door Follow-Up Phase (5/1 – 7/10/10)• Quality Assurance Operations (4/11 – 9/3/10)• Complete Questionnaire Data Capture & Processing

(5/10 – 12/20/10)• 2010 Population Counts Reported (12/31/10)

2000 CensusShort Form – Same Sex Couples

“In determining the meaning of any Act of Congress, or of any ruling, regulation or interpretation of the various administrative bureaus and agencies of the United States, the word 'marriage' means only a legal union between one man and one woman as husband and wife, and the word 'spouse' refers only to a person of the opposite sex who is a husband or wife.”

1996 Defense of Marriage Act 41

2000 CensusShort Form – Same Sex Couples

How the Census Bureau Calculates number of same sex couples:• Collect information on the sex of everybody in the household• Relationships of everybody in the household• If two responses as “husband/wife” or “umarried partner”

they counted as same sex coupleTotal Households 105,380,101 100.00%

Heterosexual Households

59,969,000 56.91%

Spouse

54,493,232 51.71%

Umarried Partner 5,475,768 5.20%

Same Sex Couples

665,523 0.63%

336,001 0.32%

Female

329,522 0.31%

2000 CensusLong Form

Distributed to 1/6 people (appx 16.5%)Includes 52 questions on 34 subjectsPersonal subject areas include

– Social– Economic

Housing subject areas include– Physical– Financial

2000 CensusDistribution

FTP – File Transfer Protocol AFF – American Fact Finder DVD – Order DVD or CD ROM from the census

bureau Private Data Repackagers – Combine and make it

“easier” to use

2000 CensusDistribution

FTP AFF DVDDifficulty High Low LowCost No No YesUser Level High All AllSpeed Variable High N/AConnection Issues Possible Unlikely N/A

Download Limits None 5 MB CD Size

Graphical User Interface

None Yes Yes

2000 Census Public Use Microdata Samples

5% or 1% sample of individual responses to census data (micro data)

Create your own tables using raw data• Value of 2 bedroom, hispanic owned houses

• Education, occupation and citizenship status of people born in Senegal

Larger geographies• Public Use Microdata Areas (PUMAs)

Census GeographyLegal Areas

Nation State Counties Cities Townships Congressional Districts School Districts Native American Reservations

Census GeographyCensus Designated Areas

Metropolitan Statistical Area Urbanized Area and Urban Cluster Census Tract Block Group Block Zip Code Tabulation Area PUMAS/Super-PUMAS Traffic Analysis Zones

Census GeographyMain Hierarchy

Census GeographySmall Area Geographies

Census GeographySmall Areas - Blocks

Smallest units of data tabulationCover the entire nationDo not cross census tracts or countiesGenerally bounded by visible features and

legal boundariesBlock numbers completely different from 1990Size: average about 100 people

Census GeographySmall Areas - Blocks

Census GeographySmall Areas – Block Groups

Groups of blocks sharing the same first digitSmallest areas for which sample data availableSize: optimally 1,500 people, range between

300 to 3,000

Census GeographySmall Areas - Tracts

For the first time for Census 2000: Cover the nation

Relatively homogenous population characteristics

65,000 Census tracts across U.S.Size: optimally 4,000 people, range between

1,000 and 8,000

Census GeographySmall Areas – Block Groups and Tracts

Census GeographySmall Areas - Places

Incorporated Places Census Designated Places

Census GeographyMinor Civil Divisions or Census County Divisions

Census GeographySmall Areas - Counties

• Counties in 48 States• Independent Cities in 4 States• Parishes in Louisiana• Cities and Boroughs in Alaska

Census GeographyLarge Geographic Areas

Regions Divisions States Metropolitan Areas Urbanized Areas American Indian Reservations Alaska Native Areas Hawaiian Home Land Areas Zip Code Tabulation Areas (ZCTAs) Public Use Microdata Areas (PUMAs) 59

Census GeographyLarge Areas - Regions and Divisions

Census GeographyLarge Areas - Metropolitan Areas

Defined by the Office of Management and Budget (OMB)

Made up of a county or counties (or equivalent entities)

Contain large population nucleusHigh socioeconomic integration

Census GeographyLarge Areas - Metropolitan Areas

Metropolitan Statistical Area (MSA): One city with 50,000 or more inhabitants or a Census-defined urbanized area and a total metropolitan population of at least 100,000 (75,000 in New England)

Consolidated Metropolitan Statistical Area (CMSA): Meets MSA standards and population > 1 million, separate standard-meeting components can be identified, and local opinion supports component areas

Primary Metropolitan Statistical Area (PMSA): Components that make up a CMSA

Note: In 2003 new standards will go into effect. 62

Census GeographyLarge Areas – Metropolitan Areas

Census GeographyLarge Areas – Urbanized Areas

Densely settled areas with population of at least 50,000

Geographic core of block groups or blocks that have a population density of at least 1,000 people per square mile – Urban Cluster

Standards just released for Census 2000 tabulation in March 2002

www.census.gov/geo/www/ua/ua_2k.html

Census GeographyLarge Areas – Urbanized Areas

Census GeographyPublic Use Microdata Areas (PUMAs)

American Community Survey

• Conducted every year• Mail survey, interview by phone, field

representative visit• Goes out to about 3 million households• Will average responses for 3 year period to

provide small area data• Large area data will be published every year• Will replace long form in 2010 census

2010 Census

• 74% Participation

The US Census and Secondary Data Sources

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