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Data Resources Guide: Glossary

The State Library of North Carolina is a Coordinating Agency of the State Data Center. Contact us for assistance with demographic questions regarding North Carolina geographies.

Useful Terms

ACS (American Community Survey)

This survey provides demographic, social, housing and economic estimates in the form of 1-year, 5-year estimates based on population thresholds.  Findings are published annually.


The Census Bureau will not disclose private information identifying individuals or businesses guaranteed by Title 13 of the United States Code.

Confidence Interval

In the American Community Survey (ACS), a ninety percent certainty that the actual data estimate is between the upper and lower boundaries of the Margin of Error (MOE). 

CPS (Current Population Survey)

Cross Tabulation

A table showing a relationship between two variables. For example, a table showing both age and race.

Decennial Census

The census of population and housing, taken by the Census Bureau in years ending in 0 (zero). Article I of the Constitution requires that a census be taken every ten years for the purpose of reapportioning the U.S. House of Representatives. Title 13 of the U. S. Code provides the authorization for conducting the census in Puerto Rico and the Island Areas.

Enumeration -

The actual counting of the people.


Data derived from sampling.


The U.S. Census Bureau defines ethnicity in two minimum categories: Hispanic or Latino and Not Hispanic or Latino. Race and Hispanic origin are two separate and distinct concepts, while Hispanics and Latinos may be of any race.

Family Income

The combined income of family members aged 15 and up. 

Group Quarters

 A place where people live or stay, in a group living arrangement, owned or managed by an entity or organization providing housing and/or services for the residents. Group quarters include such places as dormitories, residential treatment centers, skilled nursing facilities, group homes, military barracks, correctional facilities, mental hospitals, and shelters.


All people living within a housing unit.  


The middle value in a set of numbers.

MOE (Margin of Error)

A numerical range expressing the confidence in which a figure is accurate.

NAICS (North American Industry Classification System)

See for 

Poverty Threshold

A set income amount used to determine if a certain family size falls below the the rate determined to mark poverty.  See Poverty Thresholds by year and family size:


Data collected by self identification usually in the categories of  White, Black or African American, American Indian or Alaska Native, Asian, and Native Hawaiian or other Pacific Islander.  Self identification allows individuals to select more than one race. 

SIC (Standard Industrial Classification)

A numerical classification system identifying types of industry used before the introduction of NAICS (North American Industry Classification System).

For more terms see: US Census Bureau Glossary

Census Geographies

Standard Hierarchy of Census Geographic Entities


American Indian, Alaska Native, Native Hawaiian Area 


This is the smallest geographic unit data is provided for, but only in the Decennial Census. 

BG (Block Group)

An area of between 600 and 3,000 people that make up Census Tracts.  Ideally a Census Block Group consists of 1,500 people.  This is the smallest geographic unit covered by the ACS. 

BNA (Block Numbering Area)

Geographic entities similar to census tracts, and delineated in counties (or the statistical equivalents of counties) without census tracts.  State agencies and American Indian tribal authorities, sometimes with extensive assistance from the Bureau of the Census, delineated BNAs. The Census Bureau uses census tracts and BNAs to collect, organize, tabulate, and present the results of its decennial censuses. 

Census Tract (CT)

An area of population from 1,200 to 8,000 people created for the purpose of publishing data. Census tracts are small, relatively permanent geographic entities within counties (or the statistical equivalents of counties) delineated by a committee of local data users. Generally, census tracts have between 2,500 and 8,000 residents and boundaries that follow visible features

Congressional District

An area from which US House of Representatives are elected. 

County Subdivision

Geographic divisions within a county, often a township in North Carolina counties. 

Federal Information Processing Series (FIPS)

A numeric code 

Metropolitan Statistical Area

A geographic entity designated by the federal Office of Management and Budget for use by federal statistical agencies. An MSA consists of one or more counties


An incorporated area.

School District

A geographic area in which state, county, and local officials provide education.


An electoral and administrative district of a county.

ZCTA (Zip Code Tabulation Areas)

These geographic areas roughly correspond to 3 and 5 digits of US Postal Service Zip Code areas.