Sources and Notes for Neighborhood Profiles
This page provides basic information for interpreting the indicators in the neighborhood profiles and describes the sources of data used to create them. If you have additional questions, please contact us at info@neighborhoodinfodc.org
Select the heading for sources and notes on topics of interest.
General Notes
Data used to create the Neighborhood Profiles comes from a variety of sources, including the decennial U.S. Census, the American Community Survey, and local administrative data sources. NeighborhoodInfo DC standardizes these data to allow comparisons of consistent indicators across different geographic areas and years.
Some of the source data are provided for geographic areas, such as Census tracts and block groups, which do not line up perfectly with other D.C. geographies (e.g. wards, zip codes, etc). NeighborhoodInfo DC has mapped these data to each set of geographical boundaries using population weights to split tracts or block groups, when necessary. As a consequence, some of the data in the Neighborhood Profiles by ward, Advisory Neighborhood Commission (ANC), neighborhood cluster, Police Service Area (PSA), and zip code are close approximations, rather than precise counts.
NEW: Data have been added to the profiles based on the American Community Survey (ACS) 5-year estimates. The ACS is a national survey of households and housing units, administered by the U.S. Census Bureau on an ongoing basis. The ACS replaces the decennial Census long form, which was administered only once every ten years, collecting much of the same information on demographics, poverty, employment, housing, and other detailed characteristics. While the ACS offers the advantage of more frequent data collection, it has a smaller sample size than the long form. To obtain reliable estimates for small areas, multiple years of ACS data must be combined to produce a single indicator. For subareas in DC, we must use the ACS 5-year estimates, which combine data for 60 consecutive months of surveys.
The ACS data in the neighborhood profiles are based on the first release of 5-year ACS data for 2005 through 2009. These indicators are labeled as "2005-09" in the profiles. The actual value can be thought of as an average over this 5-year period.
More information on the ACS can be found on the Census Bureau's web site.
Geography
ANCs: Advisory Neighborhood Commissions (ANCs) are political jurisdictions designed to represent the views of neighborhood residents to the District government. There are 37 ANCs in the city, each of which has an advisory board made up of neighborhood residents.
Census tracts: Census tracts are locally-defined statistical areas used by the U.S. Census Bureau for collecting and tabulating census data. Most tracts have between 2,500 and 8,000 persons and, when first defined, are intended to be homogeneous with respect to population characteristics, economic status, and living conditions. Tract definitions change every 10 years with the decennial census. For Census 2000, 188 tracts were defined for the District of Columbia. All data in the Neighborhood Profiles has been standardized to 2000 census tract boundaries to allow comparisons across different census years. Note: We do not provide profiles for six (6) census tracts that had fewer than 100 persons living in them as of Census 2000.
City: This geographic level is for the entire District of Columbia. No comparison data columns are provided in the city profile.
PSAs: Police Service Areas (PSAs) are 45 administrative areas defined by the Metropolitan Police Department for the purposes of organizing policing activities and reporting crime statistics. Note: A recent announcement from MPD notes that PSA 306 is to be transfered to the second district and renamed PSA 208. This change is not yet reflected in our neighborhood profiles, and so at this time the PSA is still refered to as 306. We apologize for any inconvenience.
Neighborhood clusters: Neighborhood clusters are 39 areas developed by the DC Office of Planning in consultation with citizens. They are meant to represent clusters of two or more neighborhoods. Neighborhood clusters were used in developing the Strategic Neighborhood Action Plans (SNAPs).
We do not use single neighborhoods as a geography because there is a substantial amount of debate about the boundaries of single neighborhoods and these boundaries tend to change over time even where there is agreement. While the boundaries of neighborhood clusters may move over time, these are designated by the District and all boundaries and changes are publically available.
Wards: The District's eight wards are the major political jurisdictions within the city. Each ward has an elected member on the Council of the District of Columbia. The ward boundaries used for these profiles were defined in 2002 using population counts from Census 2000.
ZIP codes: ZIP codes are set by the U.S. Postal Service (USPS) for the purpose of facilitating the delivery of the U.S. mail. ZIP code boundaries are not fixed; they can change over time based on the needs of the USPS. Some ZIP codes do not even represent geographic areas, but rather might be assigned to post offices or other mail delivery locations. We have created profiles for the 28 most common 5-digit ZIP codes that cover Washington, D.C.
Columns
This ANC/Cluster/PSA/Tract/Ward/ZIP Code: Numbers in this column are indicator values for the geographic area listed at the top of the profile.
Average: Average values for the indicator across all geographic areas of the same type in the city (for example, the average of all neighborhood clusters, if you are looking at a neighborhood cluster profile). For an indicator like population, the value is the average (not total) population of all geographic areas of the same type. (For the total city population and other city-level indicators, access the city profile.)
Low: The lowest values of the indicators across all geographic areas of the same type.
High: The highest values of the indicators across all geographic areas of the same type.
Population
Sources: CensusCD Neighborhood Change Database (NCDB) (1980 to 2000) created by GeoLytics and the Urban Institute with financial support from the Rockefeller Foundation (2003). The NCDB is based on Decennial Census data from 1980, 1990, and 2000, remapped to 2000 census tract boundaries.
American Community Survey (ACS) (2005-09). An ongoing survey administered by the U.S. Census Bureau. For more information, see the General Notes section.
Decennial Census (2010). The most recent US population count. The data used in the profiles are the PL94-171 Redistricting data for the District of Columbia, released on March 24, 2011.
Notes: Population for 1980, 1990, 2000, and 2010 is based on the Decennial Census counts in those years. Population for the 2005-09 ACS data are not based on the 2010 Census, however, but on U.S. Census Bureau estimates.
Children are all persons under 18 years old.
% same house 5 years ago is the percentage of individuals (excluding children under 5 years old) who lived in the same house 5 years ago as they do today. These data are only available for the decennial censuses because this question is not included in the ACS.
Population by Race/Ethnicity
Sources: CensusCD Neighborhood Change Database (NCDB) (1980 to 2000) created by GeoLytics and the Urban Institute with financial support from the Rockefeller Foundation (2003). The NCDB is based on Decennial Census data from 1980, 1990, and 2000, remapped to 2000 census tract boundaries.
American Community Survey (ACS) (2005-09). An ongoing survey administered by the U.S. Census Bureau. For more information, see the General Notes section.
Decennial Census (2010). The most recent US population count. The data used in the profiles are the PL94-171 Redistricting data for the District of Columbia, released on March 24, 2011.
Notes: Respondents in the decennial census are asked to identify separately both their race and their ethnicity. For Census 2000 and 2010, respondents were given a choice of six racial categories: White, Black or African American, American Indian and Alaska Native, Asian, Native Hawaiian and Other Pacific Islander, and "some other race"; and two ethnicity categories: "Hispanic or Latino" and "not Hispanic or Latino." In our neighborhood profiles, "% other race non-Hispanic" includes all persons other than White, Black or African American, and Hispanic or Latino.
For the first time with Census 2000, respondents were able to choose more than one racial category. A total of 14,661 persons in the District of Columbia (about 2.6 percent of the city's population) identified themselves as "multiracial" in Census 2000; 17,316, or 2.9 percent, in Census 2010. For comparability with earlier census years, when respondents were allowed to choose only one race, the NCDB reassigns multiracial persons to single race categories based on a series of decision rules. We used an identical process to reassign multiracial persons for Census 2010. For more details on this process, see the NCDB Data Users Guide.
For the ACS 5-year data, insufficient information is provided on respondents choosing multiple racial categories to allow similar bridging to single race groups. Therefore, individual racial/ethnic ACS data in the profiles do not include any multiracial persons.
Family Risk Factors
Sources: CensusCD Neighborhood Change Database (NCDB) (1980 to 2000) created by GeoLytics and the Urban Institute with financial support from the Rockefeller Foundation (2003). The NCDB is based on Decennial Census data from 1980, 1990, and 2000, remapped to 2000 census tract boundaries.
American Community Survey (ACS) (2005-09). An ongoing survey administered by the U.S. Census Bureau. For more information, see the General Notes section.
Poverty rate is the percentage of all persons living in families with incomes below the federal poverty threshold, out of persons for whom poverty status was determined. Poverty status is not determined for certain classes of people, such as those who live in institutions or other group quarters. The amount of the poverty threshold varies by family size and is adjusted annually for inflation.
Unemployment rate is the percentage of all civilians 16 years and older who were not employed at the time of the decennial census and have looked for work during the previous 4 weeks (e.g. by visiting an employment agency or writing cover letters). Civilians 16 years old or older who have been given temporary layoffs and are available to work are designated as "unemployed," even if they are not seeking work. For the ACS, the definitions of employed and unemployed are based on the respondent's status during the previous week.
% pop. 16+ yrs. employed is the percentage of all persons 16 years and older who were employed in the civilian labor force or who were in the armed forces.
% persons without HS diploma is the percentage of persons 25 years and older who have not earned a high school diploma or GED certificate.
% female-headed fam. w/kids is the percentage of female-headed families and subfamilies with own children, out of all families and subfamilies with own children. Subfamilies include persons with their own children who are not the head of household. For example, a woman with her own child who lives with her mother (the child's grandmother) would be counted as a separate subfamily if the grandmother is the head of household.
Isolation Indicators
Sources: CensusCD Neighborhood Change Database (NCDB) (1980 to 2000) created by GeoLytics and the Urban Institute with financial support from the Rockefeller Foundation (2003). The NCDB is based on Decennial Census data from 1980, 1990, and 2000, remapped to 2000 census tract boundaries.
American Community Survey (ACS) (2005-09). An ongoing survey administered by the U.S. Census Bureau. For more information, see the General Notes section.
Notes: % HHs with a phone is the percentage of households that had a working telephone in their home.
% HHs with a car is the percentage of households that had one or more passenger cars, vans, and pickup or panel trucks of one-ton capacity or less kept at home and available for the use of household members.
Child Well-Being Indicators
Sources: % children in poverty: CensusCD Neighborhood Change Database (NCDB) (1980 to 2000) created by GeoLytics and the Urban Institute with financial support from the Rockefeller Foundation (2003). The NCDB is based on Decennial Census data from 1980, 1990, and 2000, remapped to 2000 census tract boundaries.
% children in poverty: American Community Survey (ACS) (2005-09). An ongoing survey administered by the U.S. Census Bureau. For more information, see the General Notes section.
% low weight births and % births to teen mothers: Vital statistics data from the D.C. Department of Health, Center for Policy, Planning and Epidemiology.
Notes: % children in poverty see notes on poverty rate.
% low weight births is the percentages of total live births where the baby weighed under 5.5 pounds at the time of birth.
% births to teen mothers is the percentages of total live births to mothers who were under 20 years old.
Income Conditions
Sources: CensusCD Neighborhood Change Database (NCDB) (1980 to 2000) created by GeoLytics and the Urban Institute with financial support from the Rockefeller Foundation (2003). The NCDB is based on Decennial Census data from 1980, 1990, and 2000, remapped to 2000 census tract boundaries.
American Community Survey (ACS) (2005-09). An ongoing survey administered by the U.S. Census Bureau. For more information, see the General Notes section.
Notes: Family incomes are adjusted to constant dollars using the Consumer Price Index (CPI).
Public Assistance
Sources: Data on enrollment in the Food Stamp and Temporary Assistance to Needy Families (TANF) programs are provided through agreement with the D.C. Department of Human Services, Income Maintenance Administration (IMA). Note that these are raw numbers and not percentages so cannot be directly compared with across geographies, where total populations may differ (e.g some wards are more populous than others).
Notes: Annual data provided here are averages of two monthly snapshots of program enrollment for January and July. "Persons receiving..." are persons who have applied for, and have been determined by IMA to be eligible to receive, benefits under the respective programs for the particular month. To protect confidentiality, data are suppressed if there were fewer than 5 persons receiving benefits in a geographic area for the year.
Housing Conditions
Sources: CensusCD Neighborhood Change Database (NCDB) (1980 to 2000) created by GeoLytics and the Urban Institute with financial support from the Rockefeller Foundation (2003). The NCDB is based on Decennial Census data from 1980, 1990, and 2000, remapped to 2000 census tract boundaries.
American Community Survey (ACS) (2005-09). An ongoing survey administered by the U.S. Census Bureau. For more information, see the General Notes section.
Decennial Census (2010). The most recent US population count. The data used in the profiles are the PL94-171 Redistricting data for the District of Columbia, released on March 24, 2011.
Notes: Occupied housing units for 1980, 1990, 2000, and 2010 are based on the Decennial Census counts in those years. Housing unit counts for the 2005-09 ACS data are not based on the 2010 Census, however, but on U.S. Census Bureau estimates.
Vacancy rate is the total number of occupied housing units divided by the total number of housing units. Similarly, homeownership rate is the total number of owner-occupied housing units divided by the total number of housing units
Housing Market (Single-Family Homes)
Sources: Historical property sales file created by NeighborhoodInfo DC from extracts of the Property Owner Points data set. This data set contains points that represent the approximate location of real property lots within the District of Columbia as well as information about the most recent property sale. Each property point is generated based on a corresponding record maintained within the D.C. Office of Tax and Revenue (OTR) Real Property Tax Administration's (RPTA) real property database and is provided through an agreement with the D.C. Office of the Chief Technology Officer (OCTO).
Notes: Sales and sales prices are only for single-family homes, that is, condominiums and cooperatives are not included. Sales prices and changes in sales prices have been adjusted to constant dollars using the Consumer Price Index (CPI). The median sales price and price changes are not shown if there were fewer than 10 total home sales in the year.
Mortgage Lending (Home Purchase Loans)
Sources: Federal Financial Institutions Examination Council, Home Mortgage Disclosure Act (HMDA) data. HMDA was enacted by Congress in 1975 and is implemented by the Federal Reserve Board's Regulation C. This regulation provides public loan data that can be used to assist in determining whether financial institutions are serving the housing needs of their communities; public officials in distributing public-sector investments so as to attract private investment to areas where it is needed; and in identifying possible discriminatory lending patterns. HMDA reporting requirements apply to certain financial institutions, including banks, savings associations, credit unions, and other mortgage lending institutions.
Notes: Data presented here are for home purchase loans, that is, mortgage loans secured by and made for the purpose of purchasing a dwelling, including single-family, condominium, and cooperative housing units. Total housing units (for "Loans per 1,000 housing units") are from Census 2000. Borrower incomes and changes in borrower incomes have been adjusted to constant dollars using the Consumer Price Index (CPI).
Subprime loans are all loans made by mortgage lenders determined by the U.S. Department of Housing and Urban Development (HUD) to be subprime specialists. Subprime loans are those that have higher costs (such as higher interest rates) than prime loans. Subprime loans are designed for applicants with poor credit histories, high loan-to-home-value ratios, or other credit risk characteristics that would disqualify them from lower cost, prime-rate loans. HUD classifies mortgage lenders as subprime specialists if subprime loans account for at least half of their conventional (i.e., not government-backed or insured) business. HUD also uses feedback from lenders, policy analysts, and housing advocacy groups to update the list of subprime lenders. (For more on subprime lending in Washington, D.C., and the region, visit the NeighborhoodInfo DC subprime lending web page.)
Loans per 1,000 housing units is the number of new home purchase loans per 1,000 of total housing units.
Reported Crimes (per 1,000 pop.)
Sources: Preliminary Part I Crimes provided through agreement with the Metropolitan Police Department (MPDC), Central Crime Analysis Unit.
Notes: Data provided by MPDC were tabulated by the Urban Institute for NeighborhoodInfo DC. To obtain rates, we divided by the Census 2000 population. Profiles exclude undated cases and cases for which no geography could be identified. Part I crime figures are preliminary and are subject to change due to late reporting.
Part I Crimes are particularly serious offenses that local law enforcement must report to the FBI on a regular basis. The FBI include these part I crimes in their Federal Bureau of Investigations's (FBI) Universal Crimes Report. Part I violent crimes include murder, rape, aggravated assault, and robbery. Part I property crimes include arson, burglary, larceny-theft, and motor vehicle theft.
Sources and notes updated March 25, 2011.
