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. NeighborhoodInfo DC standardizes these data to year 2000 boundaries for census tracts, block groups, and addresses to enable comparisons across different census years.
Census tract boundaries do not line up perfectly with other D.C. geographies (e.g. wards, zip codes, etc), so NeighborhoodInfo DC has mapped the census tract data to each set of geographical bounadires using population weights to split tracts 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 apprioximations rather than precise counts.
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 these 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) 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.
Notes: Children are all persons under 18 years of age.
% 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. This data is only available for the decentennial census because this question is not included in the ACS interum year surveys.
Population by Race/Ethnicity
Sources: CensusCD Neighborhood Change Database (NCDB) 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.
Notes: Respondents in the decennial census are asked to identify separately both their race and their ethnicity. For Census 2000, 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 13,446 persons in the District of Columbia (about 2.4% of the city's population) identified themselves as "multiracial" in Census 2000. For comparability with earlier census years, the NCDB reassigns multiracial persons to single race categories based on a series of decision rules. For more details on this process, see the NCDB Data Users Guide.
Family Risk Factors
Sources: CensusCD Neighborhood Change Database (NCDB) 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.
Notes: Public assistance income includes general assistance and Temporary Assistance to Needy Families (TANF). Separate payments received for hospital or other medical care (vendor payments) are excluded. Supplemental Security Income (SSI) is a nationwide U.S. assistance program administered by the Social Security Administration that guarantees a minimum level of income for needy aged, blind, or disabled individuals. In 1980 and 1990, the Census provided a single count of all persons who received either public assistance or SSI. Starting in 2000, however, separate counts were given for each group. It is not possible, therefore, to provide a comparable 2000 indicator for "% HHs on public assistance/SSI."
Unemployment rate is the percentage of all civilians 16 years old and over who are not employed at the time of the 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.
% persons without HS diploma is the percentage of persons 25 years and older who have not earned a high school diploma or GED.
% 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.
Isolation Indicators
Sources: CensusCD Neighborhood Change Database (NCDB) 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.
Notes: HHs is "heads of household," which is the person, or one of the people living in the house, apartment, or mobile home who is the renter or owner. If no such person exists, any adult who is living or staying in the surveyed residence can be designated as the head of household.
Child Well-Being Indicators
Sources: % children in poverty: CensusCD Neighborhood Change Database (NCDB) 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.
% 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: % low weight births and % births to teen mothers are percentages of total births.
Income Conditions
Sources: CensusCD Neighborhood Change Database (NCDB) 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.
Notes: Family incomes for 1979 and 1989 are adjusted to constant 1999 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) 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.
Notes: 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 July 28, 2008.