The American Community Survey (ACS) replaces the decennial Census long-form sample, which provided detailed demographic, social, economic and housing data for the nation between 1960 and 2000. It represents a significant advance over the long-form sample in that data are provided more than once a decade and on a more timely basis, generally in the year after the survey is taken. The ACS uses a continuous “rolling” national sample of about 240,000 addresses a month. In order to have a large enough sample from which to create estimates of characteristics, the ACS “rolls-up” the sample for one-year, three-year or five-year periods, depending on the size of the geographic area. Estimates are prepared using 12 months of sample for places of at least 65,000 residents, 36 months of sample for places of at least 20,000 residents, and five-years of sample for all places regardless of size. This means that estimates can be for a single year (e.g. 2009) or for multi-year periods (e.g. 2006-2008, 2007-2009 and 2005-2009). The ACS provides annually updated estimates for all person and housing characteristics, which represents a significant improvement over data previously available only from the ten-year cycle census.

For New York City and the five boroughs, separate estimates are available annually. While the same is technically true for the Public Use Microdata Areas (PUMAs) – approximations of Community Districts – many cells in the tables and data profiles provided by the Census Bureau have been suppressed because of confidentiality concerns and the absence of sufficient sample for reliable estimates. As a result, we provide PUMA estimates for a three-year period, based on 36 months of sample. While these numbers represent an average for a characteristic over a three-year period, the increased reliability of the estimates makes it well worth the tradeoff. Please see the 55 PUMAs that approximate New York City’s 59 Community Districts. By late 2010, the Census Bureau will be releasing characteristics information for the 2005-2009 period, for all census tracts in New York City for the first time, using 2000 census tract definitions. Five years of sample is the minimum required to create estimates for census tracts; however, we are recommending that data users consider aggregating census tracts to increase the reliability of estimates using the Neighborhood Projection Areas geographic template available under Bytes of the Big Apple on the City Planning web site. There are 188 Neighborhood Projection Areas, making this geography a good compromise between PUMAs and census tracts.

For more information on how to use ACS data, please see The Decennial Census and the American Community Survey (ACS).

Population Estimates provide the latest available information on New York City's population preprared by the U.S. Census Bureau and evaluated by the Department of City Planning.

This report presents an analysis of New York City’s population projected through 2040. The projection was done for each of the city’s five boroughs by age and sex, at five year intervals for 2010 through 2040.

The projections were created using a cohort component model, which breaks down population growth into three main components: births, deaths, and migration. The cohort component model uses births, deaths, and migrants to move age/sex cohorts forward through time, creating a new age/sex distribution at each five year time point. A particular cohort's ability to grow or decline is dependent on how these components affect each age/sex group. The success of the model depends on identifying appropriate fertility, mortality, and migration rates to apply to different age groups.

The full report has three sections. The first section presents population projections for 2010-2040 for the total population of the city and the five boroughs. The section focuses on projections for persons of school-age (5 to 17 years) and those 65 years and over. It also includes a discussion of the planning/housing component that was used to corroborate the cohort-component projections. The second section discusses these projections in the context of New York City’s recent demographic past (1950-2010). The third section consists of two detailed appendices. Appendix I presents the underlying demographic assumptions made in these projections along with a detailed description of the data and methodology employed. While the projections in this report focus primarily on the total population, those of school-age, and the population 65 and over, Appendix II of this report provides detailed tables with projected populations for all age groups by sex and by borough. The briefing booklet provides a condensed version of the projected population to 2040.

This paper seeks to assess how social, demographic, and economic conditions in LowerManhattan have changed in the first half of this decade.

The decennial census long form,which is sent to approximately one-in-six households, has been the primary source ofsmall area social and economic data used by local policy makers, program planners, andservice providers. These data provided detailed information on those who resided inLower Manhattan in April 2000, and on the huge flows of workers into and out of thatarea. With these data becoming largely irrelevant due to the dramatic changes broughtabout by 9/11, it was crucial to gain an understanding of Lower Manhattan’s populationin the post-9/11 period to help advance the rebuilding process.

The dislocation brought about by catastrophic events, such as 9/11, are often manifested in changes in the agestructure of the population, the composition and living arrangements of households, andpatterns of migration. Furthermore, because the number of persons who work in LowerManhattan is so large, understanding post-9/11 changes in the flow of workers, their mode of transportation to work, and the origins of their work trips could be brought to bear on decisions about rebuilding infrastructure and investments in programs for these populations. Without an alternative to the traditional census long form, the city would have to wait until 2012 for a post-9/11 view of Lower Manhattan.

This document provides a neighborhood map depicting projected population growth between 2000 and 2010. This analysis is based on net new construction between 2000 and 2006, as well as units added due to alterations of existing buildings during this period, and on permits in the pipeline that are likely to result in new housing between 2006 and 2010.

Data and boundary files used in historical population density maps were provided by the Minnesota Population Center's National Historical Geographic Information System at the University of Minnesota.

• Data depicted on the "Population by Nativity" chart was derived from:
  Lobo, Arun Peter and Salvo, Joseph J. 2004. The Newest New Yorkers 2000: Immigrant New York in the New Millennium. New York: Department of City Planning
• Rosenwaike, Ira. 1972. Population History of New York City. Syracuse, NY: Syracuse University Press
• United States Census Office. 1901. Census Reports Volume 1, Twelfth Census of the United States, 1900. Washington, DC: Government Printing Office
• University of Virginia Library, Historical Census Browser

The capacity of the American Community Survey (ACS) to replace the decennial census long form is based on the validity and reliability of these data at the census tract-level. This research builds on an earlier analysis of ACS test data for the Bronx that utilized special three-year averages for neighborhoods, which were census tract aggregates. The availability of census tract data for the Bronx, which are five-year averages, provides an ideal opportunity to ask about the quality and usefulness of these data, which will become available for all census tracts in 2010. This study evaluates the reliability of these census tract attributes against those provided by the 2000 Census. Further, we attempt to gauge the usefulness of these estimates by comparing the ACS five-year averages to administrative data at the census tract level for selected population, housing and economic items.

The American Community Survey (ACS) has replaced the decennial census long form, based on the premise that the ACS is capable of creating an accurate and useful socioeconomic picture of sub-county areas, such as neighborhoods in large cities. This study compares estimates from the 1999-2001 ACS and the 2000 Census for 88 neighborhoods in Bronx County, New York. It asks whether estimates from the ACS can replace those from the census sample by drawing a picture of similarities and differences; meaningful differences are defined in this study as those that can affect the work of a large city planning agency. The results show that, despite some important conceptual differences, most estimates from the 1999-2001 ACS do not differ from those in the 2000 Census in a meaningful way; however, there are some important exceptions. Examining differences in the context of the data collection effort (mail return rates, household nonresponse rates) and in terms of data quality (item allocation levels) leads to a better understanding of differences between the two surveys.

Using the 2000 US Census and the 2007 American Community Survey (ACS), this Census Brief examines changes in employment and commuting patterns in New York City and the New York City Metropolitan Area from 2000 to 2007. Between 2000 and 2007, concurrently with large employment increases, there was a pronounced shift in the New York Metropolitan Area from auto commuting to public transportation. While this shift was most pronounced in the New York City, it existed in the suburbs as well. These findings represent a reversal of the trend from 1980 to 2000, in which transit commuters decreased as a share of all workers in the city.