Introduction to US Census DataUnderstanding, Finding, & Accessing Data

Frank Donnelly, Geospatial Data Librarianfrancis.donnelly@baruch.cuny.edu

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

https://tigerweb.geo.census.gov/tigerweb/

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

data.census.gov

https://data.census.gov/

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/