American Community Survey (ACS)

The Census Bureau encourages users to compare 2006 ACS data with data from other sources. Guidance is needed before drawing conclusions because in some instances comparisons could be misleading due to differences in questions or methods. This page provides three forms of guidance - general guidance, item-specific guidance, and examples. For all comparisons of differing time periods, users should take into consideration that geographic boundaries for the area of interest may have changed.

General Guidance

Our general guidance for comparing 2006 ACS data with data from the 2005 ACS and with Census 2000 is provided below.

Comparing 2006 ACS Data to 2005 ACS Data - The 2006 ACS includes the Group Quarters (GQ) population whereas the 2005 ACS does not. A GQ is a place where people live or stay that is normally owned or managed by an entity or organization providing housing and/or services for the residents. These services may include custodial or medical care as well as other types of assistance, and residency is commonly restricted to those receiving these services. People living in group quarters are usually not related to each other. Group quarters include such places as college residence halls, residential treatment centers, skilled nursing facilities, group homes, military barracks, correctional facilities, workers' dormitories, and facilities for people experiencing homelessness. Many types of GQ populations have demographic, social, or economic characteristics that are very different from the household population. The inclusion of the GQ population in the 2006 ACS could therefore have a noticeable impact on the distributions of these characteristics. This is particularly true for areas with a substantial GQ population.

For most population subjects, the Census Bureau suggests that you make comparisons only if the geographic area of interest does not include a substantial GQ population. For most housing subjects, the Census Bureau supports comparisons being made.

Comparing 2006 ACS Data to Census 2000 Data - There are global differences that exist between the 2006 ACS and Census 2000. These include differences in residence rules, universes, and reference periods. For example, the 2006 ACS uses a "two-month" residence rule - defined as anyone living for more than two months in the sample unit when the unit is interviewed whereas Census 2000 used a "usual residence" rule - defined as the place where a person lives or stays most of the time.

The Census Bureau subject matter specialists have reviewed all of these factors and have determined that for most population and housing subjects, comparisons can be made.

Item-Specific Guidance

Specific item-level guidance is provided in the table below. This table identifies all items included in the ACS. Scroll down the first column to find the item of interest. Specific guidance is given for each item on comparing 2006 ACS data with data from Census 2000 and with data from the 2005 ACS. Selecting "more info" links you to a detailed explanation of why we recommend to "Compare with Caution" or "Do Not Compare" the data. Generally, when it is recommended to "Compare" the data, no additional information is provided. However, in cases where additional information is needed, it is provided. Selecting "table crosswalk" links you to information that identifies the 2006 ACS tables for a specific item and the corresponding tables in the Census 2000 Summary File (SF 3) for that item. In most cases, the ACS table is structured exactly the same as the SF 3 table. However, there can be instances in which the ACS table shows more detail or shows less detail than the SF 3 table.

For a complete list of changes between the 2006 ACS and the 2005 ACS tables, please see "list of changes between 2005 and 2006 detailed tables" (Excel file.)

Examples

"Examples" are provided to demonstrate how one would navigate through the web site to get guidance on a particular subject of interest.

* Each subject area is listed with its 2-digit code. This code corresponds to the second and third characters of the ACS table number. For example, Table B08303 - Travel Time to Work - has the digits of "08" in the second and third position. This corresponds to the subject Journey to Work; Workers; and Commuting.
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