Supporting Other Disciplines

• Review (by Nieuwenhuis, et al.) of 513 neuroscience articles in five top-ranking journals (Science, Nature, Nature Neuroscience, Neuronand The Journal of Neuroscience) found:– More studies had used an incorrect statistical

procedure than a correct procedure;– The classic error was misunderstanding of a P-value

• NIH funds ~$5 billion in neuroscience research annually

• Nieuwenhuis, et al., “Erroneous analyses of interactions in neuroscience: a problem of significance”, Nature Neuroscience (2011).

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Geographic Areas: American Community Survey

Overview

• Basic Census Bureau geography

• Geographic areas for which ACS data are available

• Geographic area concept and definition issues to be aware of when using ACS data

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Types of Geographic Areas

• Legal/administrative areas (e.g., states)– have legally described boundaries; they may

provide governmental services or may be used to administer programs

• Statistical areas (e.g., tracts, PUMAs)– defined primarily for data tabulation and

presentation purposes

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Census Geographic ConceptsLegal/Administrative and Statistical Areas

Legal/Administrative Areas Statistical Areas

Nation Regions

States Divisions

Counties Census County Divisions

Minor Civil Divisions Census Designated Places

Incorporated Places Metropolitan and Micropolitan Statistical Areas

Congressional Districts Urban / Rural Areas

School Districts Census Tracts

Voting Districts Block Groups

ZIP Code Tabulation Areas Public Use Microdata Areas

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ACS Geographic Area Types U.S. and Puerto Rico

Type of Geographic AreaTotal

Number of Areas

Percent of Areas with a Population of 65,000 or more

States, District of Columbia, and Puerto Rico 52 100

County or equivalent 3,221 26

Congressional Districts 435 100

Public Use Microdata Areas 2,101 100

Metropolitan and MicropolitanStatistical Areas 955 55

http://www.census.gov/acs/www/data_documentation/areas_published/

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Hierarchy of Census Geographic Entities

*Decennial census data also have a block level on which all other geographies are built

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Hierarchy of Census Geographic Entities

• Metropolitan Areas• Counties

• Census Tracts

http://www.citylab.com/crime/2015/04/1968-and-the-invention-of-the-american-police-state/391955/

Overview

• Basic Census Bureau geography

• Geographic areas for which ACS data are available

• Geographic area concept and definition issues to be aware of when using ACS data

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Tracts and Block Groups

• Census tracts are small, relatively permanent statistical subdivisions of a county

• Block groups are statistical subdivisions of census tracts and are the lowest level of geography available in the ACS

• Block group estimates prior to 2013 release are available only in the ACS Summary File, not American FactFinder

• Block groups and tracts are available only in the ACS 5-year estimates

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Kalamazoo County, MI -Census Tract 30.04

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Kalamazoo County, MI - Census Tract 30.04, Block Groups 1, 2, & 3

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ZIP Code Tabulation Areas

• First available in the 2007-2011 ACS 5-year estimates

• Abbreviated form-ZCTAs (“zick-ta”)• Similar to U.S. Postal Service ZIP codes

For more information:http://www.census.gov/geo/reference/zctas.html

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PlacesIncorporated Places and Census Designated Places

• Incorporated Places– Legally bounded entity– Referred to as cities, boroughs, towns, or villages,

depending on the state

• Census Designated Places (CDPs)– Statistical entity– Created to present census data for an area with a

concentration of population, housing, and commercial structures that is identifiable by name, but not within an incorporated place

– Examples: Columbia, MD; Paradise, NV

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Urban AreasUrbanized Areas and Urban Clusters

• Urbanized Areas– 50,000 or more people

• Urban Clusters – 2,500 up to 49,999 people

• Both defined after each decennial census

• 2012 ACS Estimates and subsequent ACS estimate years reflect Urban Areas defined using the 2010 Census results

• Data available for urban areas aggregated within nation, states, and counties (sumlev 400, 410, 430)

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Rural Areas

All territory not within an urban area

Cuts across other hierarchies

Can be in metropolitan or non-metropolitan areas

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Urban AreasUrbanized Areas and Urban Clusters in Tennessee

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Metropolitan Statistical Areas

• Defined by U.S. Office of Management and Budget

• Metropolitan Statistical Areas– Contains core Urban Area of 50,000 or more

population– Its own County, and– Surrounding counties with heavy commuting patterns

• Micropolitan Statistical Areas– Contains urban core between 10,000 – 49,999

population

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Metropolitan and Micropolitan Statistical Areas

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Partial Map of Virginia Metropolitan Statistical Areas, Urban Areas, Places

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Public Use Microdata Areas (PUMAs)

• Population of ~100,000• Cannot cross state boundaries• Composed of:

– Census tracts– Places (excluded for the new PUMA

definitions)– One or more Counties – Combination of Tracts and Counties

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Public Use Microdata Areas

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• PUMAs are “smallest” geography available nationwide in 1-year aggregate data

• Can connect to microdata for further analysis

Overview

• Basic Census Bureau geography

• Geographic areas for which ACS data are available

• Geographic area concept and definition issues to be aware of when using ACS data

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Geographic Boundaries

• Multiyear estimates are based on geographic boundaries as of January 1 of the last year in the multiyear period

• Legal area changes are recorded in the Boundary and Annexation Survey (BAS)

• Statistical areas are updated every decade in conjunction with the decennial census

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Topics and Variables

• Files in online folder– Subjects– PUMS data dictionary– Full Summary File

structure

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Resources for Topics

• censusreporter.org– Topics -> Table Codes

• https://www.census.gov/programs-surveys/acs/– Technical Documentation

• Summary File -> Sequence Table Lookup• PUMS -> PUMS Documentation -> PUMS Technical Documentation

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