Introduction to US Census DataUnderstanding, Finding, & Accessing Data
Frank Donnelly, Geospatial Data [email protected]
Baruch College CUNY
The US Census
It’s not just the count that takes place every 10 years:
I Rich collection of several datasets
I Summarizes people, houses, and businesses by place andsubject
I Geographically detailed
I Collected over varying periods of time
I Uses consistent definitions and terminology
I Individual responses are confidential
I Data is collected for statistical purposes
I All questions and datasets have some basis in federal law
Choices and Filters
I Dataset
I Timeframe
I Topics /Subject
I Geography
Today’s Topics
Choices: Datasets and Filters
Data Sources
Advanced Topics
Decennial CensusDataset # 1
I 100% count of the population
I Taken every ten years on April 1st
I US Constitution, Article I Section 2
I Data published down to census block level
I Series: PL 94-171, Summary File 1, Summary File 2
I 2010 & 2020 Census: basic demographic variables
2010 & 2020 Census Data
I Population
I Age and sex
I Race and Hispanic origin
I Households and families
I Family relationships
I Housing units
I Housing occupancy and tenure
American Community SurveyDataset # 2
I Launched in 2005
I Rolling sample survey of 3.5 million addresses
I Estimates with margins of error
I 1 year averages for geographies with 65K+ people
I 5 year averages for all geographies down to census tracts
I Released in autumn each year for the previous year
I “Usable” data published down to census tract level
ACS Data
I All variables published in the decennial census
I Educational enrollment & attainment
I Income & poverty
I Ethnicity & language
I Labor force & journey to work
I Home value, rent, & other characteristics
I And a lot more...
Census tract: statistical area designed to have an optimalpopulation size of 4,000 people (range of 1,200 to 8,000)
The Decennial Census vs the ACSCensus Tract 68, New York County, NY
2010 Census
I 7,614 residents
I 5,414 White
I 330 Black
I 560 Hispanic
I 1,080 Asian
I 230 Other
2008-2012 ACS*
I 6,383 residents +/- 817
I 4,716 White +/- 735
I 297 Black +/- 187
I 469 Hispanic +/- 186
I 725 Asian +/- 295
I 176 Other +/- 156
* 90% Confident that population is between 5,566 and 7,200
Population Estimates ProgramDataset # 3
I Annual estimates created using calculations factoring inbirths, deaths, and migration with 10-year census asbaseline
I Data limited to basic variables: total population, sex, age,race, housing units
I Data includes components of change (births, deaths,migration)
I Geography is limited to nation, states, counties, cities,and metro areas
Time Frame
I Decennial census, every ten years for years ending in zero
I ACS, annually as 1-year period and 5-year periodestimates
I Pop estimates, annually as a vintage
Census Subject Categories
Source: F. Donnelly, Exploring the US Census, 2020
Census Universe
ACS Table B23025: Employment StatusTable universe: Population 16 Years and Over
Total:I In labor force
I Civilian labor forceI EmployedI Unemployed
I Armed Forces
I Not in labor force
Census Geography
Source: F. Donnelly, Exploring the US Census, 2020
Neighborhoods versus Census Geography
PUMAs
Census Tracts
ZIP / ZCTAs
NTAs
Today’s Topics
Choices: Datasets and Filters
Data Sources
Advanced Topics
Data Profiles
Provide a wide range of variables for one place. Good forgeneral overview, fact finding, and gaining familiarity with thecensus. Sources that provide profiles typically draw data fromfive tables published by the Census Bureau:
I Decennial Census
DP-1 Profile of General Population and HousingCharacteristics
I American Community Survey
DP02 Selected Social CharacteristicsDP03 Selected Economic CharacteristicsDP04 Selected Housing CharacteristicsDP05 Demographic and Housing Estimates
Profile Sources
Missouri Census Data CenterPoint and click to create profiles for any US geographyhttp://mcdc.missouri.edu/
NYC Population Factfinder
Map-based interface for finding profiles for neighborhoodshttps://popfactfinder.planning.nyc.gov/
Sample Questions
Missouri Census Data Centerhttp://mcdc.missouri.edu/
1. How does rent in my city (place) compare to aneighboring city or my state as a whole?
2. How many home owners are there relative to renters inmy ZIP Code?
NYC Population Factfinder
https://popfactfinder.planning.nyc.gov/
1. How does rent in my neighborhood compare to anadjacent neighborhood or my borough as a whole?
2. How many home owners are there relative to renters inmy census tract?
Tables
Census data is packaged in tables arranged in subjects.Different prefixes indicate the breadth and depth of the table.
S1903 Median Income in the Past 12 Months vsB19013 Median Household Income in the Past 12 Months
ACS Decennial Census
Data Profiles DP 02 through 05 DP 1
Summary Tables S subject table QT quick table
Detailed Tables B base tableC collapsed table
P population subjectH housing subject
Today’s Topics
Choices: Datasets and Filters
Data Sources
Advanced Topics
ACS Data & Coefficient of VariationEvaluate How Good an Estimate Is
CV measures relative amount of sampling error associatedwith an estimate.
CV of Population by Race
CV = ((MOE / 1.645) / Estimate)*100(1.645 is Z value for 90% confidence interval)
New York County Census Tract 68White population: 9 (0-15 highly reliable)Hispanic population: 24 (16 to 34 medium reliability)Black population: 38 (35 + low reliability)
ACS Data & Derived EstimatesExample: Sum Population of Two Tracts
Sum of Total Population for 2008-2012 ACS
Tract 68 (6,383 +/- 817) and Tract 64 (7,439 +/- 621)
6,383 + 7,439 = 13,822SQRT((817ˆ2)+(621ˆ2)) = 1,026
Tract Combo Population at 90% confidence is:13,822 +/- 1,026
(90% confident that pop is between 12,796 and 14,848)
ACS Data and Mapping
https://atcoordinates.info/2020/03/23/
kids-with-no-internet-at-home-data-processing-for-us-census-mapping/
Census API
https://github.com/frankpd/census_api_examples
Dataset Summary
Use decennial census:
I Need actual counts
I Data for smallest geographies
I Basic demographic variables
I Long-term historical comparisons
Use ACS:
I Recent data
I For detailed social & economic characteristics
I Use 1-year period only for largest areas / groups
I Use 5-year period for everything else
Use population estimates:
I Basic demographics for large geographic areas
I Annual components of change
I Simple dataset
Census Book
Exploring the US Census: Your Guide to America’s DataSAGE Publications, 2020
https://atcoordinates.info/census-book/