About the Census & the Annual American Community Survey



  • straight count of people who live in the U.S. Provides basic demographics – sex, age, race, Hispanic origin, and homeowner status (aka ‘tenure’)
  • Mandated by the Constitution.
  • Takes place every 10 years.
  • Determines the number of seats each state has in the U.S. House of Representatives.
  • Used to distribute billions in federal funds to state and local communities.
  • Now asks 10 “short form” questions (starting with Census 2010). Here’s a copy of the short form questionnaire:  Census 2010 Questionnaire


American Community Survey Estimates

Prior to the 2010 census, a ‘long form’ questionnaire was used to gather statistical data about the U.S. population.  This detailed information painted a picture of the demographic, social, and economic face of the nation – from states to counties to census tracts.   See sample here:  Census 2000 Long Form Questionnaire

Because data from the decennial census arrived in 10-year intervals, there was no way to harness and analyze population trends and other changes in the intervening years.

Congress asked the Census Bureau to bridge this gap with information and data about how the lives and circumstances of Americans change in those in-between years.

The American Community Survey estimates (ACS) is the result.

  • American Community Survey shows how people live.
  • ACS is the source for demographic and socio-economic data – citizenship, educational attainment, income, home ownership, travel time to work… and data is available, down to small areas (census tracts- about 4,000).
  • Annual data for the ACS is acquired from a series of detailed questions asked of each respondent, and is not unlike the old ‘long form’ questionnaire of decennial census 2000 and earlier; here’s a sample ACS Questionnaire.

Subjects included in the ACS survey


Each year, we get three types of datasets:

  • ACS 1-year estimates for populations of 65,000+ (2014)
  • ACS 3-year estimates for populations of 20,000+ (2011-2013)
  • ACS 5-year estimates for populations of any size (2010-2014)

This comparison table, courtesy of the ACS site, is helpful in determining which estimates one should consider using when looking for particular data.

1-year estimates 3-year estimates 5-year estimates
12 months of collected data 36 months of collected data 60 months of collected data
Data for areas with populations of 65,000+ Data for areas with populations of 20,000+ Data for all areas
Smallest sample size Larger sample size than 1-year Largest sample size
Less reliable than 3-year or 5-year More reliable than 1-year; less reliable than 5-year Most reliable
Most current data Less current than 1-year estimates; more current than 5-year Least current
Best used when Best used when Best used when
Currency is more important than precision

Analyzing large populations

More precise than 1-year, more current than 5-year

Analyzing smaller populations

Examining smaller geographies because 1-year estimates are not available

Precision is more important than currency

Analyzing very small populations

Examining tracts and other smaller geographies because 1-year estimates are not available



Understanding NYC Geographies

This very helpful Guide to Finding NYC Neighborhood Census Data, published by Baruch College, summarizes the different geographies (Census Tract, Public Use Microdata Areas, Neighborhood Tabulation Areas…) that are used to study our neighborhoods, and points to the available datasets for each geography.

Public Use Microdata Area(s) approximate New York City’s 59 community districts -about 100,000 persons.  A Census Bureau creation; there are 55 PUMAs in NYC. Here is a map of NYC PUMAs and Community Districts

Neighborhood Tabulation Area(s) are subsets of New York City’s PUMAs.  Created by the NYC Department of City Planning for presenting published census data; the Census Bureau does not publish data for NTAs.  The City created these 195 areas by aggregating census tracts based on neighborhoods.  Find Census Tract-to-PUMA-to-NTA equivalencies here:  NTA, census tract and PUMA equivalency.


Useful Tools for Finding Census Data for NYC Neighborhoods 

NYC Department of City Planning  is the prime stop on the trek for New York City census data.  Access is provided to the Decennial Census (2010), the ACS Survey, the NYC Census Factfinder, and Population Estimates for NYC.

When comparing CDs within a borough, SocialExplorer (CUNY J-School) has an easy-to- use interface.  Have a look at Barbara Gray’s excellent how-to for finding community data with SocialExplorer here: Tipsheet

Note: Income Data in SocialExplorer is adjusted for inflation.

Infoshare  (CUNY J-School).  Search by CD or neighborhood. Data tends to be not as current as found using SocialExplorer.  Income data is not adjusted for inflation! Use an inflation calculator.  To convert dollar values from earlier Census data to current values use the Consumer Price Index (calculator here)

Note:  The Census questionnaire requires respondents to report their income for the previous calendar year (e.g., for 2009 in the 2010 survey).

Census Reporter  is a tool for journalists (funded by the Knight News Challenge) to help reporters use American Community Survey census data to write stories.

The U.S. Census’ New American Factfinder is the repository for all things census; include the American Community Survey, the Decennial Census, the Annual Economic Surveys, the American Housing Survey, the Economic Census (published every five years); here’s the release schedule for releases of the most recent economic census (2012).



Making Comparisons

Be careful when comparing sets of ACS dataThis Census Bureau link will prove invaluable:  ACS/Census Table Comparisons

  • DO compare similar period lengths, e.g. 3-year to 3-year.
  • DON’T compare estimates from different period lengths, e.g. 1-year to 3-year.
  • DO compare estimates from non-overlapping periods, e.g. compare a 2005-2007 ACS 3-year estimate to a 2008-2010 ACS 3-year estimate.
  • DON’T compare overlapping periods, for example, the 2005-2007 ACS 3-year estimates to the 2006-2008 ACS 3-year estimates. 


Use ACS data to generate story ideas

  • Compare data year over year in an area to identify trends.
  • follow Barbara Gray’s Twitter list Census for Journos
  • Use latest data to examine how they affect your beat or community.
  • Take a national story, and localize it.
  • If you hear about a trend or issue on your beat, use Census data to illustrate or disprove.
  • All ACS data are estimates; you should ALWAYS identify them as such.  To help interpret the reliability of the estimate, a margin of error (MOE) is included for every ACS estimate.


Census Database Help

If you’re ever unsure about how to find or use specific data, call the Census Bureau’s Subject/Topic Contacts; you’ll need to be on the American Factfinder site when you call, so they can walk you through.  Or contact the bureau’s New York Regional Office


There’s No Religion Data in the US Census!

  • The Association of Religion Archives and Data (ARDA)  ARDA Archives and Data has produced a 2010 study of US congregations and membership; data tracks to the state and county level.