Data

The Census Bureau polls 100% of the households in the US with a brief questionnaire asking a limited number of questions about every household member and a number of questions about the household itself every ten years. For learning about the lives of people, the Census Bureau sends a longer questionanaire, i.e. "the long form", to two samples of households (a 5% and a 1% of sample of all households), which asks very detailed questions about the members of the household and of the household itself.

To this invaluable core data, GeoLytics has added Estimates (1997) and Projections (2002) of both Demographic (population, housing, income, etc.) and Consumer Spending Data (amount households spend on categories like clothing, food, etc.) for five geographic levels - census block group, census tract, zip code, county, and state. GeoLytics also included 26 categories of US County Time Series Statistics which provide information on subjects such as Crime, Federal Spending, Agriculture, Industry, Employment, Vital Statistics, and much more, for each of the 3,000 counties in the United States.

Geography

The core set of data in Census CD+Maps is for 16 levels of geography with the smallest being the Census Block Group. The territority of the US is organized hierarchically for the purposes of subdividing the population.

The basic organization in Census CD is like this:

• Nation (US)
• Region (Northeast, Midwest, South, and West)
• Division (New England, Middle Atlantic, East North Central, West North Central, South Atlantic, East South Central, West South Central, Mountain, and Pacific)
• States
• Counties
• Tracts
• Block groups
• Blocks
• Places
• ZIP
• MSA/CMSA
• PMSA
• Urban Area
• 104^th Congress
• American-Indian
• ANRC
• MCD (Minor Civil Divisions)

Census Blocks

These are the smallest geographic units for which the Census Bureau tabulates data. Their boundaries follow the visible features such as streets, streams, and railroad tracts. They are not split between geographical entities. The entire US were divided into more than 7 million blocks for the 1990 Census.

Block Groups

The Census Bureau divided the whole country into census block groups comprising 225,000 small areas each populated by an average of 1100 people. These are the neighborhoods people live in a street, a development, a city block, even a single city building. A block group is a cluster of blocks having the same first digit of their three digit identifying numbers within a census tract, For example, BG 3 within a census tract includes all blocks between 301 and 397.

Tracts

Tracts are small, relatively permanent subdivisions of a county. They usually have between 2,500 and 8,000 people (1,500 to 8,000 in Census 2000), and they are designed to be homogenous with respect to population characteristics, economic status, and living conditions. Census tracts do not cross county boundaries. Census tract numbers are identified by four digit basic number and may have two-digit suffix; for example, 6059.02.

Counties

The primary legal divisions of most States are termed counties. In some states (Louisiana, Alaska, Maryland, Missouri, Nevada, and Virginia), these divisions are called parishes, boroughs, or independent cities. These different names are included in county category in the Census CD.

Places

Places are primarily urban towns and cities. They include census designated places (densely settled concentrations of populations that are identifiable by name, but are not legally incorporated places) and incorporated places (they are legally recognized as cities, boroughs, towns and villages with the exceptions of the towns in a few states including New York).

MSA's

MSAs are Metropolitan Statisical areas that are relatively freestanding metropolitan areas (MAs) that are not closely associated with other MAs.

PMSA's

If a metropolitan area has more than one million persons, primary metropolitan statistical areas (PMSA) may be defined within it. PMSAs consist of a large urbanized county or cluster of counties which have strong internal economic and social linkages.

CMSA's

When PMSAs are established, the larger area of which they are component parts is designated a consolidated metropolitan statistical area (CMSA).

ANRC's

Alaska Native Regional Corporations

MCD's

Minor Civil Divsions are the primary political or administrative divisions of a county in some, but not all, states.

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What other Census products does EDS have?

In addition to Census CD+Maps for both 1990 and 1980, EDS has has two other types of Census data: Summary Data and Micro Data (PUMS).

STF's

Summary Tape files. These provide statistics for the whole and sample population. STF1 and STF2 have data for 100% population (therefore they have similar data with Census CD). STF3 and STF4 provide data for the samples of population, meaning that they display data for questions answered on the long form.

PUMS

Public Use Microdata Series which consist of the actual sample data with most of the geographical identifiers removed (geographical identifiers only exist for population groups of 100,000 or more). EDS has CD-ROMs of the 5% and 1% data for all 50 states.

The STF CD's are almost the same with Census CD, and it is more difficult to extract data from STFs than the Census CD. But, they can be used when a large number of small geographical areas (tracts, block groups), detailed subset of variables and large number of counts are needed (tailored counts option limits the number of counts to 240 in the Census CD.