Summary: | In addition
to the historic Census files, 1790-1950, ICPSR archives and
distributes Census data acquired from the United States Census Bureau
as well as files prepared by ICPSR and other principal investigators
for the decennial years 1960, 1970, 1980, 1990, and 2000. These
include major sets such as the Summary Tape/Count Files, Master
Enumeration District List (MEDList) files, and Public Use Microdata
Samples (PUMS), as well as various subsets. ICPSR's holdings of 1970
Census data include a variety of data files acquired from the United
States Census Bureau, a national-coverage file prepared by ICPSR, and
files prepared by other principal investigators. The files from the
Census Bureau are separated into three basic types: Summary Count
files, the Master Enumeration District List (MEDList) files, and
Public Use Microdata Samples (PUMS). Within these collections,
various data subsets are available, depending on the user's needs. For
example, to obtain first-count data for Minnesota's Congressional
Districts, the user can download ICPSR 8122, Summary Count 1B for
Minnesota. In addition, ICPSR 0003 contains a subset of 1970 data that
might be useful for users of the 1970 Census of Population and
Housing. This subset, the National Coverage file, contains all the
variables published in the "Advance Report of the General Population
Characteristics" obtained from the First Count of the 1970 Census. The
information in this file is presented for all counties and states in
the United States. ICPSR's holdings of the Summary Count files include
Summary Count File 1B (all states), Summary Count File 4A--Population
(all states), Summary Count File 4B--Population (most states), Summary
Count File 4C--Population (all states), and Summary Count
4A--Population and Housing (California). Summary Count Files present
tabulations for small geographic areas. First Count Summary Files
contain about 400 cells of final complete-count population and housing
data, summarized in File A for enumeration districts or blockgroups,
and in File B for states, counties, minor civil divisions (MCDs) or
census county divisions (CCDs), places, and congressional
districts. Second Count Summary Files are subdivided into File A and
File B and contain about 3,500 cells of complete-count population and
housing data summarized for each census tract in File A, and for
states, counties, MCDs or CCDs, places, and Standard Metropolitan
Statistical Areas (SMSAs) in File B. Third Count Summary Files contain
250 cells of complete-count population and housing data for each city
block in urbanized areas and other areas which have contracted for
block statistics. Fourth Count Summary Files contain 20-, 15-, and
5-percent sample population and housing characteristics organized into
three file subdivisions. Fifth Count Summary Files contain population
and housing sample data summaries for ZIP code areas. Sixth Count
Summary Files provide detailed tabulations and cross-classifications
of sample population and housing characteristics for states, SMSAs
(metropolitan counties), nonmetropolitan counties of 50,000, and
larger cities. The Master Enumeration District List (MEDList) files
provide information for geographic codes contained on census summary
tapes. They provide a listing of state, county, and area or place
names corresponding to numerical identification codes used on the
summary tapes. The 1970 MEDList is an expanded version of the 1960
Geographic Identification Code Scheme but unlike the 1960 counterpart,
the 1970 MEDList contains block and census tract codes, enumeration
district codes, and population and housing totals for enumeration
district and block groups from which congressional district and other
area totals may be summarized. Public Use Microdata Samples (PUMS)
were created by the Census Bureau since 1960 as part of each decennial
enumeration and contain individual- and household-level information
from the long-form questionnaires distributed to a sample of the
population enumerated in the Census. The PUMS make it possible for
researchers to create tabulations tailored to their particular
questions and to make time-series comparisons. In 1970, the Bureau
produced three geographic versions and created a Form 1 sample and a
Form 2 sample for each version: the state samples, the metro or county
group samples, and the neighborhood samples. The state and county
group samples have two record types: housing unit records and person
records. For each household, information is provided on the housing
unit itself, as well as on the characteristics of each person in
it. Each housing unit record is followed by a variable number of
person records, one for each member of the household or none if a unit
is vacant. A third record type is also present in the neighborhood
characteristics samples: each neighborhood characteristic record is
followed by the housing unit records sampled within the neighborhood,
which in turn are associated with person records. Because of
confidentiality reasons, the 1970 samples do not identify any places
smaller than 250,000 inhabitants. For more information, visit the IPUMS USA Web site. |
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