The Delaware Valley Regional Planning Commission (DVRPC) is an interstate, intercounty, and intercity agency serving the Philadelphia-Camden-Trenton metropolitan area. As the region's metropolitan planning organization (MPO), the Commission provides technical assistance and services to its member state and local governments. Delaware Valley Data is a periodic series of free data bulletins and analytical data reports. This report discusses the United States Census Bureau's American Community Survey (ACS), and reviews demographic changes in the Delaware Valley between 2000 and 2006 based on this survey. The ACS is a continuous household survey conducted by the Census Bureau that replaces the long-form of the traditional decennial Census. It provides annual descriptions of the characteristics of every community in the nation, rather than once every ten years. The ACS began with a demonstration project in selected counties between 1996 and 2004, and was implemented in every county in the United States beginning in January 2005. Unlike the traditional Census, ACS results are rolling estimates based on responses from a small sample collected monthly and averaged over a three to five year time period. The ACS is authorized under Title 13 of the United States Code. People who receive a survey are required by law to answer all of the questions to the best of their ability. Because of the small sample size, obtaining statistically valid results is dependent on receiving clear responses from nearly every address to which a survey is randomly sent. Although the ACS will eventually provide annual estimates of population and employment characteristics for small geographies, data is currently only available for counties and census-designated places with 65,000 or more residents. In the Delaware Valley, ACS estimates are now available for the region's nine counties and six of the region's 352 municipalities. Estimates for places with 20,000 or more residents are scheduled to be released by the Census Bureau in late 2008, and data for other census geographies is scheduled for release in late 2010. Comparisons between ACS data and other data sets, including the 2000 decennial Census, should be made with caution. Differences between the decennial Census and the ACS in terms of methodology, sample size, and wording of the questions may affect the comparability of the data. The ACS results are rolling estimates based on data collected monthly over a three to five year time period, whereas the Census is a point-in-time survey distributed to everyone at the same time and referenced to one specific date (April 1) in any given decade. The ACS estimates for the Delaware Valley show that the population of the region's nine member counties grew by approximately 2% between 2000 and 2006, from approximately 5.4 million to just over 5.5 million. The fastest growing counties in the nine county DVRPC region betweenThe Delaware Valley Regional Planning Commission (DVRPC) is an interstate, intercounty, and intercity agency serving the Philadelphia-Camden-Trenton metropolitan area. As the region's metropolitan planning organization (MPO), the Commission provides technical assistance and services to its member state and local governments. Delaware Valley Data is a periodic series of free data bulletins and analytical data reports. This report discusses the United States Census Bureau's American Community Survey (ACS), and reviews demographic changes in the Delaware Valley between 2000 and 2006 based on this survey. The ACS is a continuous household survey conducted by the Census Bureau that replaces the long-form of the traditional decennial Census. It provides annual descriptions of the characteristics of every community in the nation, rather than once every ten years. The ACS began with a demonstration project in selected counties between 1996 and 2004, and was implemented in every county in the United States beginning in January 2005. Unlike the traditional Census, ACS results are rolling estimates based on responses from a small sample collected monthly and averaged over a three to five year time period. The ACS is authorized under Title 13 of the United States Code. People who receive a survey are required by law to answer all of the questions to the best of their ability. Because of the small sample size, obtaining statistically valid results is dependent on receiving clear responses from nearly every address to which a survey is randomly sent. Although the ACS will eventually provide annual estimates of population and employment characteristics for small geographies, data is currently only available for counties and census-designated places with 65,000 or more residents. In the Delaware Valley, ACS estimates are now available for the region's nine counties and six of the region's 352 municipalities. Estimates for places with 20,000 or more residents are scheduled to be released by the Census Bureau in late 2008, and data for other census geographies is scheduled for release in late 2010. Comparisons between ACS data and other data sets, including the 2000 decennial Census, should be made with caution. Differences between the decennial Census and the ACS in terms of methodology, sample size, and wording of the questions may affect the comparability of the data. The ACS results are rolling estimates based on data collected monthly over a three to five year time period, whereas the Census is a point-in-time survey distributed to everyone at the same time and referenced to one specific date (April 1) in any given decade. The ACS estimates for the Delaware Valley show that the population of the region's nine member counties grew by approximately 2% between 2000 and 2006, from approximately 5.4 million to just over 5.5 million. The fastest growing counties in the nine county DVRPC region between