GLOSSARY OF DEMOGRAPHIC TERMS

A B C D E F G H I L M N O P R S T U V W Z

-A-
 
Age –The age classification is based on the age of the person as of April 1, 1990.
Aggregate –The total amount. For example, the Aggregate Households calculates the total number of households within a specified area.
Aggregation –A process of grouping unique data. The aggregated data set has a smaller number of elements than the input data set.
American Indian, Eskimo, or Aleut –Includes persons who classified themselves as such in one of the specific race categories identified below.
American Indian - Includes persons who indicated their race as "American Indian," entered the name of an Indian tribe, or reported such entries as Canadian Indian, French-American Indian, or Spanish-American Indian.
Eskimo - Includes persons who indicated their race as "Eskimo" or reported entries such as Arctic Slope, Inupiat, and Yupik
Aleut - Includes persons who indicated their race as "Aleut" or reported entries such as Alutiiq, Egegik, and Pribilovian.
American Indian Reservation (AIR)  –American Indian entity with boundaries established by treaty, statute, and/or executive or court order. Federal and individual state governments established reservations as territory over which American Indians have governmental jurisdiction. These entities are designated as colonies, communities, pueblos, rancherias, reservations, and reserves. The Federally recognized reservations, their names, and their boundaries are identified for the Census Bureau by the Bureau of Indian Affairs (BIA), an agency in the US Department of the Interior; state governments identify the names and boundaries of state reservations.
Area –The size, in square miles, recorded for each geographic entity. Square miles may be multiplied by 2.59 to convert an area measurement to square kilometers. Land Area was calculated by the Census Bureau from the specific set of boundaries recorded for each entity in its geographic data base. 
Asian –Includes persons who classified themselves as such in one of the following specific race categories: Chinese, Filipino, Japanese, Asian Indian, Korean, Vietnamese, Cambodian, Hmong, Laotian, Thai, Other Asian.
Average –The number found by dividing the sum of all quantities by the total number of quantities. For example, Aggregate Income divided by Total Households equals Average Household Income.
Average Income of Households –Includes the income of the householder and all other persons 15 years and over in the household, whether related to the householder or not. Because many households consists of only one person, average household income is usually less than average family income.
Average Household Income –The average or mean income is obtained by dividing total household income by the total number of households. Because the average is influenced strongly by extreme values in the distribution, it is especially susceptible to the effects of sampling variability.
Average Household Size –Average household size is calculated by dividing the number of persons in households by the number of households.

-B-
 
Base Map–A map containing geographic features used for locational reference.  Roads, for example, are found on base maps.
Black  –Includes persons who indicated their race as "Black or Negro" or reported entries such as African American, Afro-American, Black Puerto Rican, Jamaican, Nigerian, West Indian, or Haitian.
Block Group (BG)–Combination of census blocks that is a subdivision of a census tract or block numbering area (BNA).  A block group consists of all blocks whose numbers begin with the same digit in a given census tract or BNA; for example, BG 3 within a census tract or BNA includes all blocks numbered between 301 and 399.  The BG is the lowest level of geography for which the Census Bureau has tabulated sample data in the 1990 census; it was used to tabulate sample data in the 1970 and 1980 censuses only for those areas that had block numbers.
Borough–Type of governmental unit, in Alaska, that is the primary legal subdivision of the organized portion of the state, similar to a county in other states.  In New York, a functioning MCD; the boroughs are the five entities, one for each county, that together constitute New York City.  In Connecticut, New Jersey, and Pennsylvania, an incorporated place; In New Jersey and Pennsylvania, also a county subdivision.  See also census area.
Boundary File –Boundary files represent bounded regions, such as a country, a state, or a census tract. Each object in a boundary file is a bounded region. For example, in a U.S. file, each state is represented by a separate polygon.

-C-
 
Census Area–Statistical equivalent of a county in Alaska.  Census areas are delineated cooperatively by the state of Alaska and the Census Bureau for statistical purposes in the portion of Alaska not within an organized borough; they were first used in the 1980 census.  See also borough.
Census Block –The smallest geographical area, bounded by visible boundaries, for which census data are collected. Census blocks make up census block groups that make up census tracts.
Census Block Group  –Subdivisions of census tracts, each representing 250-350 Housing Units.
Census County Division (CCD)–Statistical subdivision of a county, established cooperatively by the Census Bureau and state and local government authorities, for the presentation of decennial census data in 21 states that do not have well-defined MCDs; that is, where MCDs have not been legally established, do not serve a legal or administrative governmental purpose, are not well known, have poorly defined boundaries, and/or have frequent boundary changes.  A CCD boundary normally follows visible features and county lines, but may follow corporate boundaries and other non-visible features in selected instances.  See also minor civil division.
Census Designated Place (CDP)–Statistical entity, defined for each decennial census according to Census Bureau guidelines, comprising a densely settled concentration of population that is not within an incorporated place, but is locally identified by name.  CDPs are delineated cooperatively by state and local officials and the Census Bureau, following Census Bureau guidelines.  These entities were called unincorporated places for the 1940 through 1970 censuses.
Census Tract  –A small, permanent subdivision of a county with homogeneous population characteristics, status and living conditions.
Census Tract Number–Four-digit number, possibly with a two-digit suffix, used to identify a census tract.  Census tract numbers are always unique within a county and usually unique within a Metropolitan Area.  Almost all census tract numbers range from 0001 to 9499.  Leading zeros are not shown on the Census Bureau's maps or in its printed reports.
Centroid–The center of a map object.
City–Type of incorporated place in 49 states and the District of Columbia.  In 23 states, some or all cities are not part of any MCD, and the Census Bureau also treats these as county subdivisions, statistically equivalent to MCDs.
Collar Ratio –This variable is the ratio of White Collar Workers in an area to Blue Collar Workers.  This is a derived value from the 1990 Census.
Comparison Report–This report displays data of geographic areas side by side, thus comparing the areas.
Consolidated Metropolitan Statistical Area (CMSA) –Geographic entity defined by the Federal Office of Management and Budget (OMB) for use by Federal statistical agencies.  An area becomes a CMSA if it meets the requirements to qualify as a metropolitan statistical area (MSA), has a population of 1,000,000 or more, if component parts are recognized as primary metropolitan statistical areas (PMSAs), and local opinion favors the designation.  Whole counties are components of CMSAs outside of New England, where they are composed of cities and towns instead.
Consumption Expenditures –The total dollar value of all goods and services purchased by the household sector for current use.
County –The primary political administrative subdivision of a state, the county is widely used for marketing purposes for the following reasons: 1) The range and reliability of currently available data below the state level is greatest at the county level. 2) County geographic boundaries are rarely altered. 3) Complete national coverage is achieved by summarizing all counties. 4) County boundaries are readily identifiable.
For Louisiana, parishes are used in lieu of counties; for Alaska, boroughs and census areas. The District of Columbia is treated as a single county unit. In Virginia, all cities are by law independent of counties; therefore they are treated as county units. The cities of Baltimore, MD, St. Louis, MO and Carson City, NV are also independent and therefore classified as counties.

-D-
 
Demographic variable–A raw number, percentage, average, median, index value, etc. for a geographic area.  Examples: Total Population for a zip, Median Income for a country.
Density –Population divided by the county's square miles of land area. A simple basis for relating population to a county's size. Thus, two counties with the same population can have sharply divergent densities because of difference in land area. The figure may suffer because the land area will include railroad freight yards, wildlife preserves, industrial parks and other nonresidential areas, resulting in a misleading density level.
Designated Market Area (DMA)–The formal term for what is more commonly known as a TV or broadcast market.  DMA's are selected by totaling the viewer hours of TV stations whose signals reach a particular county with total hours, then converted to a percentage share of all viewing hours. DMA's are named for the market of origin of the station(s) with the largest share of viewer hours, and all counties whose largest viewer share is given to stations in that same market of origin are grouped together under that DMA.
NOTE: Because of the reach of broadcast signals, DMA's don't always conform to whole-county geography like metro markets or newspaper markets. In certain cases, Nielsen splits counties, treating each portion as if it were a separate county. Each county, or portion thereof, is allocated to a single DMA, eliminating any geographic overlap. DMA's cover the whole U.S., except for parts of Alaska.

-E-
 
Educational Attainment (25+)–The Education Attainment category provides data based on those households with individuals  25 years of age or older.  This category is displayed in the Demographic Trend reports.  The educational attainment bundle includes the following variables; Associate Degree, Bachelor's Degree, Grade 9-12, Graduate Degree, High School Graduate, Less that Grade 9, and Some College no Degree.  Data source US Census.
Education Ratio–This variable is the ratio of those individuals 25 years of age and older who completed at least a Bachelor’s Degree to those whom did not. This is a derived value from the 1990 Census.
Ethnic Population –These figures are updated from the 1990 Census of Population and Housing, comprising a head count of all persons who consider themselves of ethnic origin. The main groups are blacks, Asian/Pacific islanders, and Spanish or Hispanic. It should be noted that persons of Hispanic origin may be of any race.

-F-
 
Federal Information Processing Standards (FIPS) –Standardized system of numeric and/or alphabetic coding issued by the National Institute of Standards and Technology (NIST), an agency in the US Department of Commerce, for use by the Federal Government and others.  FIPS codes are assigned for a variety of geographic entities, including American Indian and Alaska Native area, congressional district, county, county subdivision, metropolitan area, place, and state.

The basic geographic code formats published in FIPS publications (FIPS PUBS) are (1)  states-two digits, (2)  counties and county equivalents-three digits, (3)  metropolitan areas-four digits; CMSAs have two-digit codes, (4)  congressional districts-two digits, (5)  named populated places, primary county divisions, and other locational entities used to assign codes to places, county subdivisions, and AIANAs-five digits.

The objective of the FIPS code is to improve the use of data and avoid unnecessary duplication and incompatibilities in the collection, processing, and dissemination of data.

-G-
 
Gender –Male and Female population totals.
Geocoding  –Geocoding is the process of assigning to a street address a latitude and longitude coordinate and/or geographic codes that associate an address to census geography-such as a block group, census tract, or county.
Geographic data–The location and descriptions of geographic features.  The composite of spatial data and descriptive data. 
Geographic Data Technology (GDT)–Geographic Data Technology, Inc. develops premier map databases that provide the foundation for applications such as site selection, routing packages, environmental mapping and direct marketing.
Geographic Information System (GIS)  –A computer software system with which spatial information may be captured, stored, analyzed, displayed and retrieved.

-H-
 
Hispanic Origin –Persons who classify themselves in the census as being of Mexican, Puerto Rican, Cuban or "other Spanish/Hispanic" origin. Persons of "other Spanish/Hispanic" origin are those whose origins are from Spain, the Spanish-speaking countries of Central or South America, or the Dominican Republic, or are persons of Hispanic origin identifying themselves generally as Spanish, Spanish-American, Hispanic, Hispano, Latino, and so on. Origin can be viewed as the ancestry, nationality group, lineage, or country of birth of the person or the person's parents or ancestors before their arrival in the United States. Where households or families are classified by Hispanic origin, the Hispanic origin of the householder is customarily used. NOTE: Persons of Hispanic origin may be of any race.
Household  –A household consists of all the people occupying a single housing unit under the 1990 Census rules. A housing unit is defined as a house, apartment, mobile home, group of rooms, or a single room that is occupied. In addition, the members of a household need not be related, and a single person living alone in a housing unit is also considered a household.  Persons who are not counted as members of households comprise those living in group quarters such as college dormitories, military barracks, rooming houses, long-term-care hospitals, nursing homes, and prisons.

-I-
 
Income–Income is the aggregate of wages and salaries, net farm and non-farm self-employment income, interest, dividends, net rental and royalty income, Social Security and railroad retirement income, other retirement and disability income, public assistance income, unemployment compensation, Veterans Administration payments, alimony and child support, military family allotments, net winnings from gambling, and other periodic income.
Income of Households –Includes the income of the householder and all other persons 15 years old and over in the household, whether related to the householder or not. Because many households consist of only one person, average household income is usually less than average family income.

-L-
 
Layer–Basic element of a map.  A map typically consists of several superimposed layers.  Each map layer refers to one specific table of information.
Latitude–Used to describe the North-South position of a point as measured usually in degrees or decimal degrees above or below the equator.  Latitude lines are the horizontal lines on a map that increase form 0 degrees at the Equator to 90 degrees at  both the North (+90.0 degrees) and South (-90.0 degrees) poles.
Legend–The reference area on a map that lists and explains the colors, symbols, line patterns, shadings, and annotation used on the map.  The legend often includes the scale, origin, orientation, and other map information.  
Longitude–Used to describe the East-West position of a point.  The position is reported as the number of degrees east (to -180.0 degrees) or west (to +180.0 degrees) of the prime meridian (0 degrees).  Represented by vertical lines running from the North to South poles.  Lines of longitude are farthest apart at the Equator and intersect at both poles, and therefore, are not parallel.

-M-
 
Map–An abstract representation of the physical features of a portion of the Earth's surface graphically displayed on a planar surface.  Maps display signs, symbols, and spatial relationships among the features.  They typically emphasize, generalize, and omit certain features from the display to meet design objectives (e.g., railroad features might be included in a transportation map but omitted from a highway map).
Meridian –A line running vertically from the north pole to the south pole along which all locations have the same longitude. The Prime Meridian (0) runs through Greenwich, England. From the Prime Meridian, measures of longitude are negative to the west and positive to the east up to 180, halfway around the globe.
Media Market –See designated market area.
Median –A calculated value that divides the distribution in an area into two equal parts. One half falls above the value and one half falls below. For example, if the median age is 21, half the population is younger than 21 and the other half is older than 21.
Median Age  –This measure divides the age distribution into two equal parts: one half of the cases falling below the median value and one-half above the value.
Median Income  –The median represents the middle of the income, dividing the income distribution into two equal parts, one having income above the median and the other having income below the median.
Metropolitan Statistical Area (MSA)–A geographic area with a significant population nucleus, along with any adjacent communities that have a high degree of economic and social integration with that nucleus.  Qualification of an MSA requires the presence of a city with 50,000 or more inhabitants, or the presence of a Urban Area and a total population of at least 100,000 (75,000 in New England).
Minor Civil Divisions (MCD)  –MCDs are political and administrative subdivisions of counties in 28 states.

-N-
 
New England County Metropolitan Area (NECMA)  –The U.S. Office of Information and Regulatory Affairs (OIRA), a division of the government's Office of Management and Budget, designates these alternative areas, composed of whole counties, in the six New England states for use with data not available below the county level. A NECMA includes, in addition to the county containing the principal central city of an MSA, any other county with at least half its population in that MSA.

-O-
 
Other Race –Includes all other persons not included in the White, Black, American Indian, Eskimo or Aleut and Asian or Pacific Islander race categories. Persons reporting in the "Other Race" category and providing write-in entries such as multiracial, multiethnic, mixed, interracial, Wesort, or a Spanish/Hispanic origin group (such as Mexican, Cuban, or Puerto Rican) are included here.

-P-
 
Pacific Islander –Includes persons who indicated their race as "Pacific Islander" or reported entries such as: Hawaiian, Samoan, Guamanian, Other Pacific Islander.
 Parish –Type of governmental unit that is the primary legal subdivision of Louisiana, similar to a county in other states.
Per Capita Income  –Average obtained by dividing total Income by total Population.
Percent Change in Population 
The percent change between April 1, 1990 (Census) and the current year's estimate.
 Polygon  –A class of spatial objects having area and perimeter, and representing a closed boundary region of uniform characteristics.
Population  –Updated from the 1990 Census of Population and Housing, total Population is a head count estimate of all people living in a given geographic area as of  January 1, 1997. It includes people living in group quarters, such as colleges, hospitals, institutions, and nursing homes, as well as armed forces personnel permanently assigned to the area.
Population By Age and Sex  –Male and female population totals for 11 age groups are useful for marketers who seek to aim their products or services at specific sales targets. For example, the 12- to 17-year-old population is a favorite target of those marketing soft drinks and compact disks. Several of the age groups are also associated with lifestyle stages such as the preschoolers (0-5 years), teenagers (12-17 years), and young adults (18-24 years), which are critical to the formulation of marketing strategies.
Population Per Square Mile –See density. 
Primary Metropolitan Statistical Area (PMSA)–Geographic entity defined by the Federal OMB for use by Federal statistical agencies.  If an area meets the requirements to qualify as a (MSA) and has a population of one million or more, two or more PMSAs may be defined within it if statistical criteria are met and local opinion is in favor.  A PMSA consists of a large urbanized county, or a cluster of such counties (cities and towns in New England) that have substantial commuting interchange.  When one or more PMSAs have been recognized, the balance of the original, larger area becomes an additional PMSA:  the larger area of which they are components then is designated a consolidated metropolitan statistical area (CMSA).  
PSYTE  – A segmentation system that classifies U.S. neighborhoods into 65 unique lifestyle segments developed through statistical clustering methods.

-R-
 
Race –The concept of race as used by the Census Bureau does not denote any clear-cut scientific definition of biological stock. The data for race represent self-classification by people according to the race with which they most closely identify. Furthermore, it is recognized that the categories of the race item include both racial and national origin or socio-cultural groups.

The racial categories of the 1990 census (before modification) are provided below:

• White
• Black
• American Indian, Eskimo, or Aleut
• Asian or Pacific Islander
• Other

Region – An enclosed area defined by one or more polygons. If a region contains one or more lakes or islands, each lake or island is a separate polygon.

-S-
 
School Enrollment (3+)–The School Enrollment category provides data based on those households with individuals 3 years of age or older and includes data from both private and public schools.  This category is displayed in the Demographic Trend reports.  The school enrollment bundle includes the following variables; Enrollment in College, Enrollment in Elementary/High School, Enrollment in Preprimary School.  Data source US Census.
Socioeconomic Measure  –This variable was created via a proprietary method that involved a weighting of individual demographic variables which proved to be significant in determining the overall socioeconomic status of a region. Variables included in the analysis were education, home value, income, age, ethnicity, occupational class, and many others.  Once scores were modeled, they were smoothed to maintain the bounds of 0 and 100.  We make a special note that geographic areas do not aggregate well.  Unless one is looking at small custom geographies, the scores are best used as a measure of comparison between areas of the same relative size.
Source  –The company which created the data.
State  –The primary division of the United States. The District of Columbia is treated as a state.

-T-
 
Television Market  –See Designated Market Area (DMA).
Thematic Variable –The data values displayed on a thematic map. A thematic variable can be a field or expression. 
Thematic Map–A type of map which uses a variety of graphic styles (e.g., colors or fill patterns) to display information about the map's underlying data. Thus, a thematic map of population might show one region in deep red (to indicate the population density in that region is high), while showing another region in very pale red (to indicate the population density in that region is relatively low). 
Total Income –The algebraic sum of the amounts reported separately for wage or salary income; net non-farm self-employment income; net farm self-employment income; interest, dividend, or net rental or royalty income; Social Security or railroad retirement income, public assistance or welfare income; retirement or disability income; and all other income. See Income.
Trade Area–A trade area is a user defined radius around an advertiser.
Traffic Volumes–Traffic Volumes are intersection statistics that provide detailed information on the average daily traffic count.  The data includes the traffic location and count.  Data source GDT.

-U-
 
Urbanized Area (UA)–Urbanized Areas are defined by the US Census Bureau "to provide a better separation of urban and rural territory, population, and housing in the vicinity of large places". A complete explanation of UA's, and of the criteria for delineating them, can be found on the Census Bureau's http://www.census.gov/population/censusdata/urdef.txt web site. These Urbanized Areas are used, by both government and private agencies, as a basis for determining whether specified locations ought to be considered urban (within a UA) or rural (not within any UA).

-V-
 
Variable –Input variables are organized by the category they belong to, then by the year, and then a sub-category if necessary. For example, (Category - Educational Attainment, Vintage (Year) - 1990, Variable(s) - Associate Degree and Grade 9-12).
Vintage –The date that the map or data was created or updated.

-W-
 
White –Includes persons who indicated their race as "White" or reported entries such as Canadian, German, Italian, Lebanese, Near Easterner, Arab, or Polish.

-Z-
 
ZIP Code –Administrative units established by the United States Postal Service (USPS) for the efficient distribution of mail. ZIP Codes generally do not respect political or census statistical area boundaries, nor do they usually have clearly identifiable boundaries. In addition, ZIP Codes often serve a continually changing area, are changed periodically to meet postal requirements and do not cover all the land area of the United States. The first three digits of the five-digit code identify a major city or sectional distribution center while the last two digits signify a specific post office delivery area or point.
 Zoom–To enlarge and display greater detail of a portion of a geographic data set.
Zoom Layering–A setting which determines which layers in a map window displays at any one time.