ACS Workbook A Glossary of Terms
ACS Main Window Window based on Microsoft Internet Explorer that contains links to different parts of the CD-ROM and to the Internet. The window will be the same for all screens except when working with data tables. Active Dimension The table dimension currently selected. The browser highlights the dimension to show that it is selected.  The active dimension is displayed in the Active Dimension Box. American Indian Reservation An American Indian entity with boundaries established by treaty, statute, and/or executive or court order. Federal and individual state governments have established reservations as territory over which American Indians have governmental jurisdiction. These entities are designated as colonies, communities, pueblos, ranches, rancherias, reservations, reserves, tribal towns, and villages. The federally recognized reservations and their names are identified for the Census Bureau by the Bureau of Indian Af fairs (BIA); their boundaries are identified by tribal governments. State governments identify the names and boundaries of state reservations. Bands A range of numeric values associated with a numerical source field. Beyond 20/20 Browser The program used to view and manipulate American Community Survey data tables. Block A subdivision of a census tract (or, in 1990, 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 -- e specially 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 onl y for part of the nation. (Due to confidentiality requirements, American Community Survey data cannot be viewed on a single block level; the smallest geographic group available for public use is the Block Group.) Block Group (BG) A subdivision of a census tract (or, in 1990, 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 the blocks within a census tract with the same initial di git. For example, block group 3 consists of all blocks within a 2000 census tract numbering from 3001 to 3999. In 1990, block group 3 consisted of all blocks numbered from 301 to 399Z. Block Numbering Area (BNA) Prior to Census 2000, a statistical subdivision created for grouping and numbering blocks within a county for which census tracts had not been established. For Census 2000, all counties have census tracts. Browsing Data Using the Beyond 20/20 Browser to view data in tables, charts, and maps. Census Designated Place (CDP) A 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 a 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. Code A symbolic value that uniquely identifies an item. A code can be an abbreviation, or a combination of numbers, symbols and letters. Column Distribution A calculation of the percentage distribution down the data. Dimension An aspect of the data (such as SEX or GEOGRAPHY), which is broken down into one or more items [categories] (such as male and female, or Brevard County and Multnomah County). Beyond 20/20 tables contain at least two dimensions, but can contain up to eight dimensions. When you first open a table, all of the items [categories] from two dimensions are displayed in the column and row dimensions. One item from each of the remaining dimensions is displayed in the Dimension bar. Direct Estimate A midpoint within the range of the 90-percent confidence interval designated by the upper and lower bounds. Incorporated Place All incorporated places recognized legally as in existence under the laws of their respective states as cities, boroughs, towns, and villages, with the following exceptions: the towns in the New England states, New York, and Wisconsin, and the borough s in New York are recognized as minor civil divisions for census purposes; the boroughs in Alaska are county equivalents. Item An element or category of a dimension. For example, if you were to look at the dimension of RACE, the available items would be "White," "Black," "American Indian, Eskimo, and Aleut," etc. An item may have one or more labels attached to it. Linked Data When dimensions are linked to a chart or map, the chart or map is automatically updated when changes are made within the table. In contrast, unlinking a dimension ensures that the specific dimension category in the chart or map remains constant or un changed. Minor Civil Division (MCD) A type of governmental unit that is the primary legal subdivision of a county in 28 States, created to govern or administer an area rather than a specific population. The several types of MCDs are identified by a variety of terms, such as town, townsh ip, and district, and include both functioning and nonfunctioning governmental units. Many MCDs represent local, general-purpose governmental units, which makes them required areas for presentation of decennial census data. Nest To display more than one dimension along the columns or rows in a table view by creating a series of subordinate headings. Place A concentration of population either legally bounded as an incorporated place, or identified by the Census Bureau as a Census designated place. Population Subgroup Defines specific groups within the universe of a table. PUMS The Public Use Microdata Sample files, or PUMS, are a sample of the actual responses to the American Community Survey and include most population and housing characteristics. The Microdata file will include as many records as possible and show the low est level of geography possible within confidentiality constraints. Users can then customize tabulations of the data to examine the information for detailed research and analysis or in a way that best serves their needs. Range Definitions The determination of how the data is divided (low range, middle range, high range) for graphically representing the data in maps. Recode The action of assigning one or more codes in an existing source field to one or more new items. Also referred to as grouping. Row Distribution A calculation of the percentage distribution across the data. Site The areas (usually counties) where the American Community Survey was conducted. Source Field With the PUMS data, variables, such as RACE, AGE, INCOME, and SEX are termed source fields initially. These source fields are placed into the table structure, where they then become the table's dimensions. Summary Table Summary Tables are useful pre-prepared tables of different survey items available for all levels of geography within the site (i.e., census tracts, blockgroups, places, counties, etc). Switch To change where a dimension is displayed by dropping one dimension tile on top of another. The two dimensions exchange positions. Also referred to as pivoting. Total Distribution A calculation of the percentage distribution of the total population subgroup. 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 decennial census data. Census tract boundaries normally follow visible features, but may follow govern mental 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 establ ishment, census tracts usually contain between 2,500 and 8,000 inhabitants. They may be split by any sub-county geographic entity. Universe Defines the collection of people within the survey about whom a specific table is giving information. Upper and Lower Bounds Designate the boundaries for a 90-percent confidence interval on the data estimate.  A 90-percent confidence interval can be interpreted roughly as providing 90-percent certainty that the true number falls between the upper and lower bounds.