Age
Age is generally derived from date of birth information, and is based on the age of the person in complete years.
American FactFinder
A generalized electronic system for access and dissemination of Census Bureau data. The system is available through the Internet and offers prepackaged data products and the ability to build custom tables. The system allows users to access data from the Census at various levels of geography (e.g., County, Census tract, Zip code).
Average household size
A measure obtained by dividing the number of people in households by the total number of households.
Block
A subdivision of a census tract (or, prior to 2000, a block numbering area), a block is the smallest geographic unit for which the Census Bureau tabulates 100-percent data. Many blocks correspond to individual city blocks bounded by streets, but blocks – especially in rural areas – may include many square miles and may have some boundaries that are not streets. The Census Bureau established blocks covering the entire nation for the first time in 1990. Previous censuses back to 1940 had blocks established only for part of the nation. Over 8 million blocks are identified for Census 2000.
Block group
A subdivision of a census tract (or, prior to 2000, a block numbering area), a block group is the smallest geographic unit for which the Census Bureau tabulates sample data. A block group consists of all the blocks within a census tract with the same beginning number. Geographic block groups never cross census tracts but may cross the boundaries of county subdivisions, places, urbanized areas, voting districts, and so forth. Tabulation block groups may be split to present data for every unique combination of county subdivision, place, and the like.
Example: block group 3 consists of all blocks within a 2010 census tract numbering from 3000 to 3999. In 1990, block group 3 consisted of all blocks numbered from 301 to 399Z.
Census
A complete enumeration of a population or the business and commercial establishments, farms, or governments in an area. See decennial census.
Census block
A subdivision of a census tract (or, prior to 2000, a block numbering area), a block is the smallest geographic unit for which the Census Bureau tabulates 100-percent data. Many blocks correspond to individual city blocks bounded by streets, but blocks – especially in rural areas – may include many square miles and may have some boundaries that are not streets. The Census Bureau established blocks covering the entire nation for the first time in 1990. Previous censuses back to 1940 had blocks established only for part of the nation. Over 8 million blocks were identified for Census 2000.
Census tract
A small, relatively permanent statistical subdivision of a county delineated by a local committee of census data users for the purpose of presenting data. Census tract boundaries normally follow visible features, but may follow governmental unit boundaries and other non-visible features in some instances; they always nest within counties. Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions at the time of establishment, census tracts average about 4,000 inhabitants. They may be split by any sub-county geographic entity.
Civic association
Civic associations are comprised by groups of people and households that live in the same neighborhood. In Arlington County, Civic Associations are part of the County Neighborhood Conservation Program. The County Board created the Neighborhood Conservation Program in 1964 to encourage neighborhoods to create neighborhood improvement plans and to provide dedicated funding to implement those plans.
Decennial census
The census of population and housing, taken in each year ending in zero. Article 1, section 2 of the Constitution requires that a census be taken every 10 years for the purpose of apportioning the U.S. House of Representatives. The first census of population was taken in 1790. The Census Bureau first conducted the census of housing in 1940.
Demographics
The statistical characteristics of human populations and households (such as age or income.)
Family
A group of two or more people who reside together and who are related by birth, marriage, or adoption.
Family household (Family)
A family includes a householder and one or more people living in the same household who are related to the householder by birth, marriage, or adoption. All people in a household who are related to the householder are regarded as members of his or her family. A family household may contain people not related to the householder, but those people are not included as part of the householder’s family in census tabulations. Thus, the number of family households is equal to the number of families, but family households may include more members than do families. A household can contain only one family for purposes of census tabulations. Not all households contain families since a household may comprise a group of unrelated people or one person living alone.
Group quarters
The Census Bureau classifies all people not living in households as living in group quarters. There are two types of group quarters: institutional (for example, correctional facilities, nursing homes, and mental hospitals) and non-institutional (for example, college dormitories, military barracks, group homes, missions, and shelters).
Hispanic/Latino/Spanish
A self-designated classification for people whose origins are from Spain, the Spanish-speaking countries of Central or South America, the Caribbean, or those identifying themselves generally as Spanish, Spanish-American, etc. Origin can be viewed as ancestry, nationality, or country of birth of the person or person’s parents or ancestors prior to their arrival in the United States. Spanish/Hispanic/Latino people may be of any race.
Household
A person or group of persons who occupy a housing unit as their usual place of residence. These equal the count of occupied housing units in a traditional census.
Household size
The total number of people living in a housing unit.
Household type and relationship
Households are classified by type according to the sex of the householder and the presence of relatives. Examples include: married-couple family; male householder, no wife present; female householder, no husband present; spouse (husband/wife); child; and other relatives.
Housing unit
A house, an apartment, a mobile home or trailer, a group of rooms, or a single room occupied as separate living quarters, or if vacant, intended for occupancy as separate living quarters. Separate living quarters are those in which the occupants live separately from any other individuals in the building and which have direct access from outside the building or through a common hall. For vacant units, the criteria of separateness and direct access are applied to the intended occupants whenever possible.
Long form
The decennial census questionnaire, sent to approximately one in six households for the 1980, 1990, and 2000 censuses, contains all of the questions on the short form, as well as additional detailed questions relating to the social, economic, and housing characteristics of each individual and household. Information derived from the long form is referred to as sample data, and is tabulated for geographic entities as small as the block group level in 1980, 1990, and 2000 census data products.
Mean
This measure represents an arithmetic average of a set of numbers. It is derived by dividing the sum of a group of numerical items by the total number of items in that group. For example, mean family income is obtained by dividing the total of all income reported by people 15 years and over in families by the total number of families.
Median
This measure represents the middle value (if n is odd) or the average of the two middle values (if n is even) in an ordered list of data values. The median divides the total frequency distribution into two equal parts: one-half of the cases fall below the median and one-half of the cases exceed the median.
Metro Station Area
The area surrounding each of Arlington County’s seven Metro stations. In general, a Metro Station Area includes all of the area within a quarter-mile radius of the Metro station entrance.
Neighborhood Strategy Area
Neighborhood Strategy Areas (NSAs) are low and moderate income neighborhoods in Arlington County that receive Community Development Block Grant (CDBG) funds and other resources. There are four neighborhoods designated as NSAs in Arlington: Arna Valley, Buckingham, Columbia Heights West, and Nauck.
Occupied housing unit
A housing unit is classified as occupied if it is the usual place of residence of the person or group of persons living in it at the time of enumeration or if the occupants are only temporarily absent; for example, away on vacation. Occupied rooms or suites of rooms in hotels, motels, and similar places are classified as housing units only when occupied by permanent residents, that is, individuals for whom the facility is their usual place or residence.
Own children
A child under 18 years old who is a son or daughter by birth, marriage (a stepchild), or adoption. For 100-percent tabulations, own children consist of all sons/daughters of householders who are under 18 years of age. For sample data, own children consist of sons/daughters of householders who are under 18 years of age and who have never been married, therefore, numbers of own children of householders may be different in these two tabulations.
Owner-occupied housing unit
A housing unit is owner occupied if the owner or co-owner lives in the unit even if it is mortgaged or not fully paid for.
Poverty
Following the Office of Management and Budget’s (OMB’s) Directive 14, the Census Bureau uses a set of money income thresholds that vary by family size and composition to detect who is poor. If the total income for a family or unrelated individual falls below the relevant poverty threshold, then the family or unrelated individual is classified as being “below the poverty level.”
Public Law 94-171
The public law requiring the Census Bureau to provide selected decennial census data tabulations to the states by April 1 of the year following the census. These tabulations are used by the states to redefine the areas included in each congressional district and the areas in other districts used for state and local elections, a process called redistricting.
Race
Race is a self-identification data item in which respondents choose the race or races with which they most closely identify.
Related children
Includes all people in a household under the age of 18, regardless of marital status, who are related to the householder. Does not include householder’s spouse or foster children, regardless of age.
Renter-occupied housing unit
All occupied units which are not owner occupied, whether they are rented for cash rent or occupied without payment of cash rent, are classified as renter-occupied.
Sex
An individual’s gender classification – male or female.
Short form
The decennial census questionnaire, sent to approximately five of six households for the 1980, 1990, and 2000 censuses. For Census 2000, the questionnaire asked population questions related to household relationship, sex, race, age and Hispanic or Latino origin and housing questions related to tenure, occupancy, and vacancy status. The 1990 short form contained a question on marital status. The questions contained on the short form also are asked on the long form, along with additional questions.
Spanish/Hispanic/Latino
A self-designated classification for people whose origins are from Spain, the Spanish-speaking countries of Central or South America, the Caribbean, or those identifying themselves generally as Spanish, Spanish-American, etc. Origin can be viewed as ancestry, nationality, or country of birth of the person or person’s parents or ancestors prior to their arrival in the United States.
Spanish/Hispanic/Latino people may be of any race.
Summary File 1 (SF 1)
This file presents 100-percent population and housing figures for the total population, for 63 race categories, and for many other race and Hispanic or Latino categories. This includes age, sex, households, household relationship, housing units, and tenure (whether the residence is owned or rented). Also included are selected characteristics for a limited number of race and Hispanic or Latino categories. The data are available for the U.S., regions, divisions, states, counties, county subdivisions, places, census tracts, block groups, blocks, metropolitan areas, American Indian and Alaska Native areas, tribal subdivisions, Hawaiian home lands, congressional districts, and ZIP Code Tabulation Areas. Data are available down to the block level for many tabulations, but only to the census-tract level for others. Available from the US Census Bureau on CD-ROM, DVD, and American FactFinder at www.census.gov.
Summary File 2 (SF 2)
This file presents data similar to the information included in Summary File 1. These data are shown down to the census tract level for 250 race, Hispanic or Latino, and American Indian and Alaska Native tribe categories. For data to be shown in SF 2, a population category must meet a population size threshold of 100 or more people of that specific population category in a specific geographic area. Available from the US Census Bureau on CD-ROM, DVD, and American FactFinder at www.census.gov.
Summary File 3 (SF 3)
This file presents data on the population and housing long form subjects such as income and education. It includes population totals for ancestry groups. It also includes selected characteristics for a limited number of race and Hispanic or Latino categories. The data are available for the U.S., regions, divisions, states, counties, county subdivisions, places, census tracts, block groups, metropolitan areas, American Indian and Alaska Native areas, tribal subdivisions, Hawaiian home lands, congressional districts, and Zip Code Tabulation Areas. Available from the US Census Bureau on CD-ROM, DVD, and American FactFinder at www.census.gov.
Summary File 4 (SF 4)
This file presents data similar to the information included in Summary File 3. These data are shown down to the census tract level for 336 race, Hispanic or Latino, American Indian and Alaska Native tribe, and ancestry categories. For data to be shown in SF 4, there must be at least 50 unweighted sample cases of a specific population category in a specific geographic area. In addition, the data for the specific population category for the specific geographic area must also have been available in Summary File 2. Available from the US Census Bureau on CD-ROM, DVD, and American FactFinder at www.census.gov.
Tenure
Refers to the distinction between owner-occupied and renter-occupied housing units.
Tract
A small, relatively permanent statistical subdivision of a county delineated by a local committee of census data users for the purpose of presenting data. Census tract boundaries normally follow visible features, but may follow governmental unit boundaries and other non-visible features in some instances; they always nest within counties. Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions at the time of establishment, census tracts average about 4,000 inhabitants. They may be split by any sub-county geographic entity. See tract.
Tract number
Used to uniquely identify a census tract within a county
Unmarried-partner household
Household in which the householder and his or her partner are not legally married or participating in a common law marriage.
Vacant housing unit
A housing unit is vacant if no one is living in at the time of enumeration, unless the occupants are only temporarily absent. Units temporarily occupied at the time of enumeration entirely by individuals who have a usual residence elsewhere are classified as vacant. (Transient quarters, such as, hotels, are housing units only if occupied. Thus, there are no vacant housing units at hotels and the like.) New units not yet occupied are classified as vacant housing units if construction has reached a point where all exterior windows and doors are installed and final usable floors are in place. Vacant units are excluded from the housing unit inventory if they are open to the elements. Also excluded from the housing unit inventory are units with a posted condemnation sign or units that are used entirely for nonresidential purposes.
ZIP Code
A ZIP (Zone Improvement Plan) Code is a five-, seven-, nine-, or eleven-digit code assigned by the U.S. Postal Service to a section of a street, a collection of streets, an establishment, structure, or group of post office boxes, for the delivery of mail.
The Census Bureau uses only 5-digit ZIP codes for the addresses and address ranges in most Census 2000 operations.