Geographic Areas

Block Group (BG) - A statistical subdivision of a census tract, consisting of all tabulation blocks whose numbers begin with the same digit in a census tract. For example, BG 3 within a census tract includes all blocks numbered from 3000 to 3999. BGs generally contain between 600 and 3,000 people, with an optimum size of 1,500 people. BGs never cross the boundaries of states, counties, or statistically equivalent entities, except for a BG delineated by American Indian tribal authorities, and then only when tabulated within the American Indian hierarchy. BGs never cross the boundaries of census tracts, but may cross the boundary of any other geographic entity required as a census block boundary. The BG is the lowest-level geographic entity for which the U.S. Census Bureau tabulates sample data from a decennial census.

Census Tract - Small, relatively permanent statistical subdivisions of a county or statistically equivalent entity that are updated by local participants prior to each decennial census as part of the Census Bureau's Participant Statistical Areas Program. The Census Bureau delineates census tracts in situations where no local participant existed or where state, local, or tribal governments declined to participate. The primary purpose of census tracts is to provide a stable set of geographic units for the presentation of statistical data. Census tracts generally have a population size between 1,200 and 8,000 people, with an optimum size of 4,000 people. A census tract usually covers a contiguous area; however, the spatial size of census tracts varies widely depending on the density of settlement. Census tract boundaries are delineated with the intention of being maintained over a long time so that statistical comparisons can be made from census to census. Census tracts occasionally are split due to population growth or merged as a result of substantial population decline. Census tract boundaries generally follow visible and identifiable features. They may follow nonvisible legal boundaries, such as minor civil division (MCD) or incorporated place boundaries in some states and situations, to allow for census-tract-to-governmental-unit relationships where the governmental boundaries tend to remain unchanged between censuses. State and county boundaries always are census tract boundaries in the standard census geographic hierarchy. Tribal census tracts are a unique geographic entity defined within federally recognized American Indian reservations and off-reservation trust lands and can cross state and county boundaries.

City - A type of incorporated place in all states and the District of Columbia. In agreement with the state of Hawaii, the U.S. Census Bureau does not recognize the city of Honolulu for presentation of census data. In Virginia, all cities are not part of any county, and so the Census Bureau treats them as equivalent to a county for data presentation purposes, as well as treating them as places; there also is one such independent city in each of three states: Maryland, Missouri, and Nevada. In 23 states and the District of Columbia, some or all cities are not part of any minor civil division, in which case the Census Bureau treats them as county subdivisions as well as places for data presentation purposes.

CBSAs - The U.S. Census Bureau term for a functional region based around an urban center of at least 10,000 people, based on standards published by the Office of Management and Budget (OMB) in 2000. These standards are used to replace the definitions of metropolitan areas that were defined in 1990. The term "CBSA" refers to both metropolitan statistical areas and newly-created micropolitan areas collectively. Micro areas are based around Census Bureau-defined urban cluster of at least 10,000 and less than 50,000 people.

County - The primary legal division of every state except Alaska and Louisiana. A number of geographic entities are not legally designated as a county, but are recognized by the U.S. Census Bureau as equivalent to a county for data presentation purposes. These include the boroughs, city and boroughs, municipality, and census areas in Alaska; parishes in Louisiana; and cities that are independent of any county in Maryland, Missouri, Nevada, and Virginia. They also include the municipios in Puerto Rico, districts and islands in American Samoa, municipalities in the Northern Mariana Islands, and islands in the Virgin Islands of the United States. The Census Bureau treats the District of Columbia and Guam each as equivalent to a county for data presentation purposes since those entities have no primary divisions.

State - The primary governmental divisions of the United States. In addition to the 50 states, the Census Bureau treats the District of Columbia, Puerto Rico, American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the U.S. Virgin Islands as the statistical equivalents of states for the purpose of data presentation.

United States (US) - The 50 states and the District of Columbia.

ZIP Code Area - The addresses served by a 5-digit ZIP Code established by the U.S. Postal Service to expedite the delivery of mail. Most ZIP Codes do not have specific boundaries, and their implied boundaries do not necessarily follow clearly identifiable visible or invisible map features; also, the carrier routes for one ZIP Code may intertwine with those of one or more other ZIP Codes, and therefore this area is more conceptual than geographic.

Census Designated Places (CDP) - Statistical counterparts of incorporated places that are delineated to provide data for settled concentrations of population that are identifiable by name but are not legally incorporated under the laws of the state in which they are located. The boundaries usually are defined in cooperation with local or tribal officials and generally updated prior to each decennial census. These boundaries, which usually coincide with visible features or the boundary of an adjacent incorporated place or another legal entity boundary, have no legal status, nor do these places have officials elected to serve traditional municipal functions. CDP boundaries may change from one decennial census to the next with changes in the settlement pattern; a CDP with the same name as in an earlier census does not necessarily have the same boundary. CDPs must be contained within a single state and may not extend into an incorporated place. There are no population size requirements for CDPs.

GENERAL CHARACTERISTICS

Household - All persons who occupy a housing unit. A house, an apartment or other group of rooms, or a single room, is regarded as a housing unit when it is occupied or intended for occupancy as separate living quarters; that is, when the occupants do not live with any other persons in the structure and there is direct access from the outside or through a common hall. A household includes the related family members and all the unrelated people, if any, such as lodgers, foster children, wards, or employees who share the housing unit. A person living alone in a housing unit, or a group of unrelated people sharing a housing unit such as partners or roomers, is also counted as a household. The count of households excludes group quarters.

Family - A group of two people or more (one of whom is the householder) related by birth, marriage, or adoption and residing together; all such people (including related subfamily members) are considered as members of one family.

Population - The population count or estimate used as the starting point in the estimates process.

School Age Population - All Population Ages 0 to 17 Years.

Income - The Median Household Income is the midpoint income in a ranking from low to high. Average Household Income is the sum of all incomes divided by the number of households. 

Race & Ethnicity

Asian - A person having origins in any of the original peoples of the Far East, Southeast Asia, or the Indian subcontinent including, for example, Cambodia, China, India, Japan, Korea, Malaysia, Pakistan, the Philippine Islands, Thailand, and Vietnam. It includes "Asian Indian," "Chinese," "Filipino," "Korean," "Japanese," "Vietnamese," and "Other Asian."

Black or African American - A person having origins in any of the Black racial groups of Africa. It includes people who indicate their race as "Black, African American, or Negro," or provide written entries such as African American, Afro American, Kenyan, Nigerian, or Haitian.

Hispanic or Latino - People who identify with the terms "Spanish," "Hispanic," or "Latino" are those who classify themselves in one of the specific categories: "Mexican, Mexican American, Chicano," "Puerto Rican," or "Cuban" - as well as those who indicate that they are "other Spanish/Hispanic/Latino" like those whose origins are from Spain, the Spanish-speaking countries of Central or South America, the Dominican Republic or people identifying themselves generally as Spanish, Spanish-American, Hispanic, Hispano, Latino, etc. People who identify their origin as Spanish, Hispanic, or Latino may be of any race.

Other Race (Some Other Race) - Includes all other responses not included in the "White," "Black or African American," "American Indian or Alaska Native," "Asian," and "Native Hawaiian or Other Pacific Islander" race categories described above. Respondents reporting entries such as multiracial, mixed, interracial, or a Hispanic, Latino, or Spanish group (for example, Mexican, Puerto Rican, Cuban, or Spanish) in response to the race question are included in this category.

American Indian and Alaska Native - A person having origins in any of the original peoples of North and South America (including Central America) and who maintains tribal affiliation or community attachment. This category includes people who indicate their race as "American Indian or Alaska Native" or report entries such as Navajo, Blackfeet, Inupiat, Yup'ik, or Central American Indian groups or South American Indian groups.

Two or More Races - People may choose to provide two or more races either by checking two or more race response check boxes, by providing multiple responses, or by some combination of check boxes and other responses. The race response categories shown on the questionnaire are collapsed into the five minimum race groups identified by OMB and the Census Bureau's "Some Other Race" category. For data product purposes, "Two or More Races" refers to combinations of two or more of the following race categories:

1.     White

2.     Black or African American

3.     American Indian or Alaska Native

4.     Asian

5.     Native Hawaiian or Other Pacific Islander

6.     Some Other Race

NOTE: There are 57 possible combinations involving the race categories shown above. Thus, according to this approach, a response of "White" and of "Asian" was tallied as two or more races, while a response of "Japanese" and of "Chinese" was not because "Japanese" and "Chinese" are both Asian responses. Tabulations of responses involving reporting of two or more races within the American Indian and Alaska Native, Asian, or Native Hawaiian and Other Pacific Islander categories are available in other data products.

Native Hawaiian and Other Pacific Islander - A person having origins in any of the original peoples of Hawaii, Guam, Samoa, or other Pacific Islands. It includes people who indicate their race as "Native Hawaiian," "Guamanian or Chamorro," "Samoan," and "Other Pacific Islander" or provide other detailed Pacific Islander responses. NOTE: In some reports, this category is not shown and is included in the "Asian" category.

White - A person having origins in any of the original peoples of Europe, the Middle East, or North Africa. It includes people who indicate their race as "White" or report entries such as Irish, German, Italian, Lebanese, Arab, Moroccan, or Caucasian.

Statistic Variables

Area Quintiles - Refers to a group containing 20% of the value of the area as a whole. Five Area Quintiles (A, B, C, D, and E) are used to show relative values of a variable within a study area. The quintiles are represented by color-coded blocks on a map.

Centroid - The physical center of a selected geography.

EASI Rank - A ratio-type rank for a particular geography representing the concentration of the variable compared to the average concentration. Tie scores are reported as the average of all tied numbers in sequence (if scores 1, 2 and 3 were tied, they would all be reported as 2).

EASI Score - Another relative measure using the results of the EASI Rank to arrange the values of a variable into a quintile (20% per group) frequency distribution.

Intensity - A measure of how closely each area matches a perfect score for the chosen profile. The highest possible intensity score is 100, which would mean that the EASI Rank for every factor in the Profile is 1 for a given area. As more variables are added to the User Profile, the likelihood of this outcome diminishes. A high intensity score represents a high concentration of a variable within an area, but does not necessarily imply a high quantity.

Population Centroid - The center of population in a selected geography.

Profile - A combination of variables and their weights calculated for a specific geography. It represents a weighted concentration of the selected variables relative to population.

Significant Variables Report - A special report ranking all variables in the categories selected, according to their EASI Rank. The variables with the highest rank (where 1 is highest) are displayed first.

US Quintile - A group containing 20% of the value of a variable in a study area based on a comparison to the entire USA. Five US Quintiles (A, B, C, D, and E) are used to show the relative values. The quintiles are represented on a map by color-coded blocks.

Dominant Profiles

Dominant Profile - a variable which attempts to define what is most unique about a given area. Below is a listing of names and their full description:

Above Average Education	Education Attainment, Graduate Degree (Population Aged 25+)
Apartments (20 or more units)	Housing, Occupied Structure with 20-49 Units
In the Armed Forces	Employment, Armed Forces Male (Population Aged 16+)
Very Asian	Population, Speaks Asian or Pacific Island Language (Population Aged 5+)
Below Average Education	Education Attainment, < High School (Population Aged 25+)
Blue Collar Employment	Employment, Blue Collar (Population Aged 16+)
Born in America	Population, Citizenship - Native
Expensive Homes	Housing, Owner Households Valued More than $1,000,000
House for Sale	Housing, Vacant Units For Sale
Large Families	Families, 5 Person
Lots of Cars	Households with 4+ Vehicles
Median Age	Population, Median Age
Median Income	Household Income, Median ($)
New Homes	Housing, Built 1999 or Later
No Cars	Households with No Vehicles
Not in Labor Force	Employment, Not in the Labor Force Male (Population Aged 16+)
Long Time Residents	Housing, Year Moved in 1969 or Earlier
Few Teens	Population Aged 12 to 17 Years
Old Homes	Housing, Built 1939 or Earlier
Pre-School	Population Aged 0 to 5 Years
Recent Movers	Housing, Year Moved in 1999 or Later
Available Renting Units	Housing, Vacant Units For Rent
Retired	Population Aged 65 to 74 Years
Very Rich Asians	Asian Household Income, High Income Average ($)
Very Rich Blacks	Black Household Income, High Income Average ($)
Very Rich Families	Family Income, High Income Average ($)
Very Rich Hispanics	Hispanic Household Income, High Income Average ($)
Very Rich Non Families	Non-Family Income, High Income Average ($)
Old and Rich Households	Household Head Aged 75+ and Income $200K+
Very Rich Whites	White Household Income, High Income Average ($)
Young and Rich Households	Household Head Aged <25 and Income $200K+
Service Employment	Occupation, Service (Population Aged 16+)
Very Spanish	Population, Speaks Spanish (Population Aged 5+)
Subway or Bus to Work	Employment, Public Transportation to Work (Employees Aged 16+)
Trailer Park City	Housing, Occupied Structure Trailer
Unattached	Population, Males Never Married (Population Aged 15+)
Unemployed	Employment, Unemployed Males (Population Aged 16+)
Very Rich Households	Household Income, High Income Average ($)
Work at Home	Employment, Work at Home (Employees Aged 16+)