Transcript Document

Census 2000:
Public Use Microdata Samples
and Metro Area Definitions
Presented by
Andrew Ruppenstein
September 25th, 2003
HSUG-West, Berkeley, 9/25/03
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Introduction:
Public Use Microdata Sample (PUMS)
Files
 American Community Survey (ACS)
Microdata Files
 Metropolitan Areas – Old and New
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Where Does Census Housing
Data Come From?
Decennial Census data comes from both
the short-form (100%) and the long-form
questionnaires (~1-6 households sample).
 With regard to housing, the short form
yields only tenure and occupancy data.
 The long form has 21 (some are multi-part)
questions concerning housing.
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Number of Housing Tables in
Census 2000 Summary Files:
Summary Summary
Summary Summary
File 2
File 3
File 4
File 1
17
9
146
93
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What is PUMS Data?
Public Use Microdata Sample files contain
a sample of individual housing unit and
person records from the census, along with
sample weights.
 There are two released PUMS samples –
1% and 5%. The 1% file has more detailed
characteristics. The 5% offers more
geographic detail.
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What Housing Data does
PUMS contain?
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Tenure
Units in Structure
Occupancy Status
Housing Value
Gross Rent
Rooms, Bedrooms
Age of Structure
Plumbing, Kitchen
Facilities, Vehicular, and
Telephone Availability
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Year Householder
Moved into Unit
Property Taxes Paid
Cost of Utilities
Cost of Fuels
Acreage
Rent
Mortgage Status
Second Mortgage Status
Property Insurance
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Why Use PUMS?
Summary vs. detail information
 Predefined tables vs. custom tabulations
 Restricted variables vs. full range of
available responses
 Greatest possible detail while still ensuring
confidentiality
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Census Public-Use Microdata
Samples History
1960 Census - 1% sample created as a
prototype
 1970 Census - 1% sample introduced as a
standard product
 1980 Census – 1% and 5% samples
 1990 Census - 1% and 5% samples
 2000 Census – 1% and 5% samples
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PUMS Geography
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PUMS data is available only for a specially
delineated set of geographies, PUMAs (5%) and
super-PUMAs (1%).
PUMAs have a minimum of 100,000 population,
super-PUMAs 400,000.
Super-PUMA and PUMA boundaries do not
cross state lines.
PUMAs fit within super-PUMAs.
Boundaries are drawn with some input from the
states and local area.
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California’s
2000 PUMAs
California has 62
super-PUMAs and
235 PUMAs.
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PUMS California Geography
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In California, PUMA boundaries were
constructed to follow city lines, where possible.
Example: PUMA 07000 = Fullerton City in
Orange County.
This holds less true for San Diego County and
the San Francisco Bay Area Counties, as local
input often chose to use tract boundaries.
Super-PUMA/PUMA boundaries and county
boundaries frequently coincide.
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S.F. Bay Area
PUMAs
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We are in PUMA
02403
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Microsample Areas are
Designated With a Code:
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Super-PUMAs (1%) have a 5 digit code, with the
first 2 digits as the state FIPS code. Example:
06050 (Solano and Napa Counties) (California’s
FIPS Code = ’06’). Range is 06010 – 06705.
PUMAs (5%) also have a 5-digit code. In
California , PUMA (5%) codes are lowest in the
north, and highest in the southern part of the
state. Range is 00100 – 08116. PUMA codes are
unique within the state, but may be repeated in
other states.
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Where do I get PUMS data?
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PUMS data is available free of charge in
downloadable form from the US Census Bureau:
http://www.census.gov/main/www/pums.html
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A DVD of the data will be available from the
Census Bureau in Fall, 2003. In addition to the
data it will include the Beyond 20/20 software
for accessing the data.
DataFerret also provides online access to PUMS
data:
http://dataferrett.census.gov/TheDataWeb/index.html
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The American Community Survey
(ACS) Microdata
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Microdata sample files are also currently available for
the 1996-1998 and 2000-2001 ACS data. The
technical documentation, record layout, geographies,
and content will not be same! But the same principles
for generating custom tabulations will hold true.
ACS sample sizes are much smaller. Expect a
tradeoff in accuracy vs. timeliness when deciding
whether to use decennial or ACS PUMS data.
When using PUMS, please be sure to cite both the
census source (decennial or ACS) and the data year.
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ACS Microdata for California
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ACS coverage has slowly expanded over time.
The first tabulations available are for 1996. 2005
should be the first year for which ACS has
complete coverage of the US.
The first California counties covered by the
program were San Francisco and Tulare in 1999.
2000 has tabulations for 21 California counties.
2001 has tabulations for 24. More counties were
sampled than tabulated, however.
The 2000 and 2001 ACS microdata files for
California have no county-level detail.
For more information, please see:
http://www.census.gov/acs/www/Products/PUMS/index.htm
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Metropolitan Statistical Areas – What
They Were, What They Are
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Metropolitan Statistical Area: “A
geographic entity, defined by the Federal
OMB for use by Federal statistical
agencies, based on the concept of a core
area with a large population nucleus, plus
adjacent communities having a high degree
of economic and social integration with
that core.”
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Changes
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The standards have changed 6 times since 1950,
and so the definitions (lists of areas) for
presenting metropolitan area statistics have
changed 10 times since 1950.
The June 30, 1999 definition is used for Census
2000 products.
There is a new definition as of June 6, 2003,
which will be applied to future Census Bureau
products.
The changes over time in areas defined as
“Metropolitan” mostly reflect population growth,
not changes in the defined concept.
HSUG-West, Berkeley, 9/25/03
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The Way Things
Were – 1999
Definitions:
3 CMSAs
12 PMSAs
12 MSAs
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Core Based Statistical Area (CBSA) Classification
A CBSA consists of the county or counties
associated with at least one core of 10,000 or greater
population, plus adjacent counties having a high
degree of social and economic integration with the
core(s) as measured by commuting ties.
CoreBased
BasedStatistical
StatisticalAreas
Areas
Core
MetropolitanStatistical
StatisticalAreas
Areas
Metropolitan
MicropolitanStatistical
StatisticalAreas
Areas
Micropolitan
PopulationininaaCore
Core
Population
50,000or
ormore
more
50,000
10,000toto49,999
49,999
10,000
Territory not included in a CBSA is designated as Outside
Core Based
Based Statistical
Statistical Areas.
Core
Areas.
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CBSA Building Blocks
Counties and equivalent entities throughout the United States
and Puerto Rico
Why?
Single, consistent geographic unit nationwide
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Familiar geographic units
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Stable boundaries
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Availability of a wide range of statistically reliable data
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CBSA Cores
 Census Bureau-defined urbanized areas (UAs)
 Census Bureau-defined urban clusters (UCs)—a new
geographic entity for Census 2000
Cores identify central counties of CBSAs
Central counties are those counties that:
• have at least 50% of their population in urban areas (UAs or UCs)
of at least 10,000 population; or
• have within their boundaries a population of at least 5,000 that
is located in a single urban area of at least 10,000 population
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Aggregating Counties
Commuting data are used to qualify outlying counties.
A county qualifies as an outlying county if:
• at least 25 percent of the employed residents of the
county work in the CBSA’s central county or counties, or
• at least 25 percent of the jobs in the county are accounted
for by workers residing in the CBSA’s central county or
counties
Measures of settlement structure, such as population density and
the percentage of population that is urban, are not used to qualify
outlying counties.
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Divisions of Metropolitan Statistical Areas
Metropolitan Statistical Areas containing at least one core with
a population of 2.5 million or greater may be subdivided to form
Metropolitan Divisions
A county will be identified as a main county of a Metropolitan
Division if:
 65 percent or more of its employed residents work within the
county, and
 the ratio of the number of jobs located within that county to its
number of employed residents is at least 0.75.
A main county automatically serves as the basis for forming a
Metropolitan Division.
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2003 Metro
Standards
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33 CBSAs, of which:
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7 Micropolitan Areas
and
26 Metropolitan
Areas, of which:
6 are multi-county.
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Learn More About PUMS
CENSUS
2000 Main Page:
http://www.census.gov/main/www.cen2000.html
CENSUS
2000 Support Pages:
http://www.census.gov/support/cen2000.html
CENSUS
Electronic Products Support Pages:
http://www.census.gov/tech/techtalk.html
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Learn More About Metropolitan
Areas
CENSUS
Metropolitan Areas Intro Page:
http://www.census.gov/population/www/estimates/metro
area.htm.
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And Finally…
For more information contact me via e-mail or
phone:
– [email protected]
– (916) 327-0103, x2526
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Credits:
1) Slides 5 and 8 were adapted with permission from
“Tabulating Data from the PUMS Files Using Beyond
20/20 Software” by Bill Savino, Electronic Products
Development Branch, US Census Bureau
2) Slides 21-24 were borrowed with permission from
“Metropolitan and Micropolitan Statistical Area Standards”
by Colleen Joyce, Geography Division, US Census Bureau
3) The maps on slides 10, 12 and 25 were created by Cynthia
Singer, Demographic Research Unit, California State
Department of Finance
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