Held every 10 years since 1790, the Census is the most comprehensive demographic survey in the United States. Although the questions asked change from year to year, through 2000 there were always variables related to age, race and ethnicity, languages spoken, education, ancestry, income, home ownership versus renting, and more. In theory, the Census counts every person living in the United States. While there are be portions of the population that go uncounted, it is still the closest we have to complete demographic and economic data on the U.S. population.
The Census Bureau's American FactFinder gives full access to the 2010 census, the 2000 census and partial access to the 1990 census. When comparing Census data from different years, remember that demographic definitions and other information are reported differently for each census. A variable reported in 1950 may not be available in 2000 and vice-versa.
Here is a detailed view of the data available in American FactFinder.
When researching communities we must determine how Census areas overlay with the streets and neighborhoods we know from everyday life. Neighborhoods are not official Census boundaries.
To do so determine what Census tracts best match up with your community to find the Census data you need. Tract boundaries may not match up exactly with the official New York City boundaries of your community, so you will also need to determine if you will include portions (blocks, block groups) of tracts that are not fully included in your neighborhood. If so, you'll need to use a combination of street maps, Census tract maps and block maps to define the specific area of research.
Be aware also that Census tract numbers and boundaries may change over time. For a detailed view of Census tract, block group & block information, consult the Census Bureau's Reference Maps or the mapping applications in American FactFinder by selecting Geographies, or use the New York City Department of Planning's NYC Population FactFinder.
Here is a quick guide to finding Census tables on race and ethnicity for a geographic area of your choice.
Advanced Search provides two approaches to the selection of Population Groups. The best approach for you to use depends on the population groups you are interested in, and the kind of information you want to know about them.
Start your search by clicking Race and Ethnic Groups. Then, select one of the entries listed on the Basic Groups tab. (You can select more than one group if you want.) AFF will add your choice to your search criteria, which are shown in the "Your Selections" box.
The data products available when you pick one of these entries will contain general information about your selected group (and possibly other groups). Click close on the Race and Ethnic Groups panel and view the tables.
To search a more complete list of over 2,500 race and ethnic groups, tribes, ancestries, and countries of origin defined by the Census Bureau, use the Detailed Groups tab. Remember, after you add a group to your Selections you can limit your search to a Census tract or Block.
The Census uses both common geographies such as states, counties, places (cities), as well as geography very specific to the Census. Locally designated boundaries such as community planning areas, neighborhoods, police beats, library districts, etc. are largely ignored in favor of specialized Census geography which allows for a standardized way of looking at geographies smaller than a city. The key small areas are:
For more detailed information refer to the Census Geography Reference.
Questions change from Census to Census, sometimes dramatically, which means that the statistics available change from decade to decade. For most of the 20th Century, the Decennial Census has included a “short form” with questions answered by every household in the country, as well as a “long form” that is answered by about 1 in 6 households.
As of 2010, there is no longer a Census long form. A short form, containing only questions such as age, race and ethnicity, will be sent to every household in the country. A longer questionnaire called the American Community Survey (ACS) covers questions previously appearing on the decennial long form. Since 2005, the ACS - which includes approximately 50 questions - has been sent to 1 in 40 households in the U.S. Over a period of 5 years, this approximates the number of households that would have normally filled out a long form decennial Census. Starting in 2010, aggregates of 5 years of data will be released each year. This means that fresh demographic data about the country will be available every year instead of every 10 years. Although the ACS data is only sample data, it's a great improvement in the availability of recent demographic data. Note, ACS data are available in American FactFinder.
The easiest way to find out what information is available for a specific Census is to look at the Census questionnaires. If the question wasn’t asked, the information isn’t available.
The Census Bureau's Index of Questions webpage provides questions asked for decennial censuses from 1790-2010. For copies of the original Census questionnaires since 1790, see the Census publication Measuring the Census: The Decennial Censuses from 1790 to 2000.