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Essential vocabulary


Age data is reported for five-year age groups and select summary groups such as 18 years and over.

Median age

Median age is calculated from the distribution of age by five-year groups. See Median.

Age Dependency Ratio (ADR)

Esri's Age Dependency Ratio (ADR) is a measure of the non-working age population relative to the population of working age that serves as a useful indicator of an area's age structure. Dependent populations are defined as children under 18 years of age and seniors aged 65 and older. For this measure, the population aged 18 to 64 is considered the working-age population. For more information about age dependency data, see Updated Demographics.

Esri provides three age dependency ratio measures to express the relationship between three age groups within a population:

  • The Age Dependency Ratio (ADR) is the sum of the population under 18 years of age and 65 and older divided by the working-age population aged 18 to 64.
  • The Child Dependency Ratio (CDR) is the population under 18 years of age divided by the working-age population aged 18 to 64.
  • The Senior Dependency Ratio (SDR) is the population aged 65 and older divided by the working-age population aged 18 to 64.

All ratios are then multiplied by 100.

American Community Survey (ACS)

In 2010, the Census Bureau changed how it collects decennial census data. The Census Bureau eliminated the traditional long form and now only releases decennial census data collected from the short form. The American Community Survey (ACS) is the replacement for census sample data, or long form. Data regarding income, education, employment, language, migration, citizenship, marital status, and housing characteristics, such as value and rent, is now obtained from the ACS rather than the decennial census sample.

The ACS provides data that is updated more frequently than the decennial census data. It collects and produces population and housing information every year instead of every 10 years. The ACS represents continuous measurement, or a rolling sample design. A small percentage of the population is sampled every month, and monthly samples are combined and averaged to produce one-, three-, or five-year databases. The Census 2000 sample represented approximately 1 in 6 households and one point in time: April 1, 2000. The ACS represents approximately 1 in 40 households. Its much smaller sample sizes affect data reporting and produce larger sampling errors.

Each ACS estimate is reported with a margin of error (MOE). The MOE is a measure of the variability of the estimate due to sampling error. The MOE enables data users to measure the range of uncertainty around each estimate. This range can be calculated with 90 percent confidence by taking the estimate plus or minus the MOE. For example, if the ACS reports an estimate of 100 +/- 20, there is a 90 percent chance that the value for the total population is between 80 and 120. The larger the MOE, the lower the precision of the estimate and the less confidence one should have that the estimate is close to the true population value.

For more information about the ACS, see American Community Survey.

Average household size

See Household.


A census block is a component of a block group identified by a four-digit code. Blocks are generally small in area, especially in cities. However, blocks in rural or remote areas may cover hundreds of square miles. A block code that starts with a zero indicates a water-only block.

Block group (BG)

A block group (BG) is a collection of one or more blocks and a statistical division of a census tract identified by a one-digit code. Block groups do not cross census tract, county, or state boundaries. In general, a BG is composed of 600 to 3,000 residents. A zero BG code indicates a water-only BG.

Census 2010

The U.S. Census takes place every 10 years. It is mandated by the U.S. Constitution and counts every resident in the United States. Census data is used to distribute federal funds to local communities and determine the number of seats each state has in the U.S. House of Representatives. It is used by businesses and local and state governments to analyze the underlying demographics of an area.

Data derived from Census 2010 is different than data from previous years. The most significant change is due to the Census Bureau's omission of the long form. The short census questionnaire provides only the complete counts of population, households, and housing units plus the following characteristics: sex, age, race, Hispanic origin, household relationship, occupancy, and tenure. Every other variable was previously collected from the sample long form. Now, data about income, education, employment, language, migration, citizenship, marital status, and housing characteristics, such as value and rent, is obtained from the ACS, which is separate from Census 2010.

A decennial census also includes a change in geography. For more information about the Census 2010 geography, see Census 2010 geography release.

Census Glossary

View the Census Glossary for the U.S. Census Bureau definition of attributes included in the Census and ACS databases.

Census tract

Census tracts are small statistical subdivisions of a county, typically with 1,200 to 8,000 residents. The boundaries are usually delineated by local committees and do not cross county or state lines. Tracts are identified by a six-digit code, with an implied decimal between the fourth and fifth digits.

Color-coded map

Also called a thematic map, a color-coded map displays geographic areas according to specific values. For example, it can be a map showing census tracts in different colors according to median household income, in which light green represents lower income, medium green represents a higher income level, and dark green represents the highest level. A map of drive times is another example of this type of map.

Compound annual growth rate (CAGR)

The compound annual growth rate (CAGR) is an annualized measure that describes a variable's direction (positive or negative) and magnitude of change between two distinct points in time. An annualized rate means that the resultant value reflects a rate of change covering a twelve-month time period. This component of the calculation permits the analysis of multiple growth rates between values measured from differing points in time since the change is computed using a common time period of twelve months. The compound component of the expression simply means that the annualized growth rate is repeated, or compounded, each year. Moreover, the CAGR can colloquially be referred to as growth rate, annual rate, annualized growth rate, or compound growth rate.

The CAGR is calculated using the following generalized formula:


where b is the beginning point in time, e is the ending point in time, and VARb and VARe are the variable values for these respective points in time.

For example, to compute a growth rate for total population between the years 2021 and 2026 for an area where the counts are 1,574 persons and 1,854 persons, respectively, use the following formula:


Congressional districts (CDs)

Congressional districts (CDs) are the areas from which individuals are elected to the U.S. House of Representatives. Once the apportionment of congressional seats is made based on census population counts in a state, each state establishes CDs to elect representatives. A CD is uniquely identified using a two-digit state FIPS code and a two-digit CD FIPS code.

Consumer Expenditure Surveys (CEX) data

This comprehensive database, developed by Esri, is based on a combination of the latest Consumer Expenditure Surveys (CEX) from the Bureau of Labor Statistics and Esri's Tapestry Segmentation data. Data is reported by product or service and includes total expenditures, average spending per household, and a Spending Potential Index (SPI). See Consumer Spending.

Core-Based Statistical Area (CBSA)

Core-Based Statistical Areas (CBSA), which include metropolitan and micropolitan statistical areas, are composed of one or more counties and are defined by the U.S. Office of Management and Budget (OMB). A metropolitan statistical area is affiliated with at least one urbanized area of 50,000 or more inhabitants. A micropolitan statistical area is associated with at least one urban cluster of at least 10,000 people, but fewer than 50,000.


Counties are the primary legal divisions of a state, identified by a two-digit state FIPS code and a three-digit county FIPS code. See FIPS code.

County subdivisions (CSDs)

County subdivisions (CSDs) are the primary divisions of counties and include census county divisions (CCDs), minor civil divisions (MCDs), census subareas, and unorganized territories. CSDs can be uniquely identified using a two-digit state FIPS code, a three-digit county FIPS code, and a five-digit CSD FIPS code.

Data collection

A data collection is a preassembled list of attributes that are used to enrich the input features. Collection attributes can describe various types of information, such as demographic characteristics and geographic context, of the locations or areas submitted as input features.

Some data collections can be used in all supported countries. Other data collections may only be available in one or a collection of countries. Data collections may only be available in a subset of countries because of differences in the demographic data that is available for each country.


One or more structured sets of persistent data that are managed and stored as a unit and generally associated with software to update and query the data. A simple database can be a single file with many records, each of which references the same set of fields. A GIS database includes data about the spatial locations and shapes of geographic features recorded as points, lines, areas, pixels, grid cells, or TINs, as well as their attributes.

Demographic data

Esri Updated Demographic data includes current-year estimates and five-year projections for key demographic data. With the exception of the Tapestry Segmentation data, which is not available at the BG level of geography in the standard product, all data is available at census block group, census tract, county, state, U.S., CBSA, DMA, and ZIP Code levels of geography.


The statistical characteristics of a population—income, education, race, home ownership, and so on.

Designated Market Area (DMA)

Designated Market Areas (DMAs) are television markets defined by The Nielsen Company that are revised on an annual basis. The majority of DMAs are composed of one or more whole counties, although a few include parts of counties.

Diversity index

The diversity index summarizes racial and ethnic diversity. The index shows the likelihood that two persons, chosen at random from the same area, belong to different race or ethnic groups. The index ranges from 0 (no diversity) to 100 (complete diversity). For example, a diversity index of 59 means there is a 59 percent probability that two people randomly chosen belong to different race or ethnic groups.

Economic Dependency Ratio (EDR)

Esri's Economic Dependency Ratio (EDR) measures the relationship of non-workers to the employed population. Non-workers include children, the unemployed population, and those not in the labor force (i.e., individuals that are neither working nor actively searching for work). Children are defined as the population under 16 years of age. For a discussion of economic dependency data see the Dependency Methodology.

Esri provides four separate economic dependency ratio measures to express the relationship between workers and non-workers within a population:

  • The Child Economic Dependency Ratio (CEDR) is the population under 16 divided by the total employed population.
  • The Working-Age Economic Dependency Ratio (WEDR) is the population not employed aged 16 to 64 divided by the total employed population.
  • The Senior Economic Dependency Ratio (SEDR) is the population not employed aged 65 and older divided by the total employed population.
  • Total EDR is the sum of CEDR, WEDR, and SEDR.

All ratios are then multiplied by 100. These measures exclude prisoners and the Armed Forces population.


Households in which one or more persons in the household are related to the householder (formerly, the head of the household) by birth, marriage, or adoption. The census tabulates only one family per household.

Federal Information Processing System (FIPS) code

Federal Information Processing System (FIPS) codes are numeric codes used to identify states and counties.

Group quarters population

Includes all people living in group quarters instead of housing units. Group quarters are places where people live or stay, in a group living arrangement, that is owned or managed by an entity or organization providing housing, services, or both for the residents. Group quarters population is divided into two general categories: institutional group quarters and noninstitutional group quarters. Institutional group quarters include adult correctional facilities; juvenile facilities; skilled-nursing facilities; and other institutional facilities, such as mental (psychiatric) hospitals and in-patient hospice facilities. Noninstitutional group quarters include facilities such as college and university student housing; military quarters; and other noninstitutional group quarters, such as emergency and transitional shelters for people experiencing homelessness and group homes.

Hispanic origin

Defined by self-identification, Hispanic origin refers to ethnicity, not race. Persons of Hispanic origin can be of any race.

Historical Time Series data

Esri's Historical Time Series database contains estimates for estimates for total population, households, and housing units data for every year between the prior decennial census and Esri's current estimates at all levels of geography down to the block group level. For example, the 2021 time series covers the entire decade from 2010 to 2021. Because this is a vintage-based time series, with each Updated Demographics release, the entire time series is updated to include new, yearly estimates. For more information, see Updated Demographics.

Home value

The estimate of value is presented for total owner-occupied units. For a discussion of home value projections, see Updated Demographics.

Median home value

This estimate divides the distribution of home value into two equal parts. Linear interpolation is used if the median home value is below $1,000,000. If the median is in the upper home value interval of $1,000,000 or more, it is represented by $1,000,001.


A household is an occupied housing unit. Household type is identified by the presence of relatives and the number of persons living in the household. Family households, with or without children, include married couples and other families—a male or female householder with no spouse present. Nonfamily households may be a group of unrelated persons or a single person living alone.

Average household size

Average household size is calculated by dividing the number of persons in households by the number of households.

Household income

See Income.

Household income base

This is the sum of the household income distribution.

Housing Affordability Index

Esri's Housing Affordability Index (HAI) measures the financial ability of a typical household to purchase an existing home in an area. An HAI of 100 represents an area that on average has sufficient household income to qualify for a loan on a home valued at the median home price. An index greater than 100 suggests homes are easily afforded by the average area resident. An HAI less than 100 suggests that homes are less affordable. The housing affordability index is not applicable in areas with no households or in predominantly rental markets. Esri's home value estimates include owner-occupied homes only.


Income amounts are expressed in current dollars, including an adjustment for inflation or cost-of-living increases. For more information about income projections, see Updated Demographics.

Median household income

This is the value that divides the distribution of household income into two equal parts. Pareto interpolation is used if the median is in an income interval other than the first or last. For the lowest interval, less than $10,000, linear interpolation is used. If the median is in the upper income interval of $500,000 or more, it is represented by the value of $500,001.

Per capita income

This is the average income for all persons calculated from the aggregate income of persons 15 years and older.


An index is the ratio of a local percent (rate) to a national percent (rate) or other base. An index at the national level is 100, representing overall demand. A value of more than 100 represents higher demand, and a value of less than 100 represents lower demand than the country as a whole. Using the variable of dollars spent on airline fares as an example, if you calculate the index of this variable as 100, it indicates that the area purchased airline tickets at the same rate as the national average. An index value of less than 100 indicates a value less than the national average, and a value greater than 100 indicates purchases of airline fares at greater than the national average. An index of 200 for a given study area indicates that households in the area purchase airline fares at twice the national average.

Leakage/Surplus Factor

The Leakage/Surplus Factor measures the balance between the volume of retail sales (supply) generated by retail businesses and the volume of retail potential (demand) produced by household spending on retail goods in the same industry. The Leakage/Surplus Factor, an Esri exclusive calculation, is the result of a more sophisticated approach for normalization of the gap between supply and demand. The result is an index scaled to upper and lower bound values ranging from -100 to +100. The Leakage/Surplus Factor provides users a simple way to identify business opportunity. To learn more, see Retail MarketPlace.


This is a value that divides a distribution into two equal parts. A median is a positional measure that is unaffected by extremely high or low values in a distribution that may affect an average. For more information about medians, see Understanding Medians (PDF).

Median age

See Age.

Median home value

See Home value.

Median household income

See Income.

Net worth

Net worth equals total household assets less any debts, secured or unsecured. Assets include ownership of homes, rental properties, businesses, individual retirement accounts and Keogh accounts, pension plans, stocks, mutual funds, and motor vehicles. Examples of secured debt include home mortgages and vehicle loans; unsecured debt includes credit cards and other bills or certain bank loans. Esri reports net worth for 12 intervals and for seven age of householder groups by 10 net worth intervals.

Per capita income

See Income.

Percent of Income for Mortgage

Percent of Income for Mortgage (POIFM) is similar to Esri's Housing Affordability Index, except it measures affordability from a monthly budget perspective. POIFM measures the percentage of median household income dedicated to monthly payments on a home priced at the median value. POIFM is not applicable in areas with no households or in predominantly rental markets and does not include home insurance, private mortgage insurance, or property taxes. Esri's home value estimates include owner-occupied homes only.

Places (cities and towns)

Places include incorporated places (usually cities, towns, villages, or boroughs), census designated places, and balance portions of consolidated cities. Places are uniquely identified using a two-digit state FIPS code and a five-digit place FIPS code.


This is the total number of residents in an area. Residence refers to the usual place where a person lives, which is not necessarily the legal residence. For example, college students are counted where they attend school.

Population by Generation

Esri provides six generational classifications. Born over similar spans of time, generational cohorts typically share the same life stage and life experiences. Generations are defined as follows:

  • Generation Alpha (born 2017 or later)
  • Generation Z (born 1999 to 2016)
  • Millennials (born 1981 to 1998)
  • Generation X (born 1965 to 1980)
  • Baby Boomers (born 1946 to 1964)
  • Silent and Greatest Generations (born 1945 or earlier)


Defined by self-identification, race detail from Census 2000 was expanded to include a multiracial component. For the first time, each individual could report up to six race categories, resulting in 63 possible race combinations. The six basic race categories are White, Black or African American, American Indian or Alaskan Native, Asian, Native Hawaiian or Other Pacific Islander, and some other race for persons who do not identify with one of the specified groups.


Segmentation explains customer diversity, simplifies marketing campaigns, describes lifestyle and life stage, and incorporates a variety of data. See Tapestry Segmentation.

Socioeconomic Index

Esri's Socioeconomic Index represents the relative social and economic status of the residents of each Tapestry segment. The value is a composite of specified characteristics including measures of financial well-being, educational attainment, and labor force characteristics such as employment status, occupation, and type of employment. The index is the ratio of the socioeconomic status of the Tapestry segment relative to the national average. Values above 100 indicate an above-average status.


States are identified by a two-digit FIPS code. The District of Columbia is included as a state-equivalent area in the Esri database. See FIPS code.

Tapestry Segmentation data

Esri's Tapestry Segmentation data provides an accurate, detailed description of America's neighborhoods. United States residential areas are divided into 67 segments based on demographic variables such as age, income, home value, occupation, household type, education, and other consumer behavior characteristics.

Thematic map

Also called a color-coded map, a thematic map displays study areas according to specific values. For example, it can be a map showing census tracts in different colors according to median household income, in which light green represents lower income, medium green represents a higher income level, and dark green represents the highest level. A map of drive times is another example of this type of map.


A symbol or quantity that can represent any value or set of values, such as a text string or number. Variables may change depending on how they are used and applied. Variables are also known as fields, attributes, or columns.


The vintage is the year that the demographic data represents. For example, a vintage of 2016 means that the data represents the year 2016.

Wealth Index

Esri's Wealth Index is compiled from a number of indicators of affluence that include average household income and average net worth. The concept of wealth is defined by more than above-average household income. Wealth also includes the value of material possessions and resources. Esri captures both income and the accumulation of substantial wealth, or the abundance of possessions and resources, in its identification of the wealthiest areas in the country. The index represents the wealth of an area relative to the national level. Values exceeding 100 represent above-average wealth.

ZIP Code

Created by the U.S. Postal Service to deliver the mail, ZIP Codes do not represent standard census geographic areas for data reporting. Because ZIP Code boundaries are not contiguous with census geographic areas or stable over time, data estimated for ZIP Codes is also subject to change.