SOURCES OF DATA

Natality Statistics

     Beginning in 1985, natality statistics for all States and the District of
Columbia have been based on information from the total file of records.  The
information is received on computer data tapes coded by the States and
provided to the National Center for Health Statistics (NCHS) through the
Vital Statistics Cooperative Program.  NCHS receives these tapes from the
registration offices of all States, the District of Columbia, and New York
City.  Data for Puerto Rico, the Virgin Islands, and Guam for 1985 are also
based on information from the total file of records.  Information for the
Virgin Islands and Guam is obtained from microfilm copies of original birth
certificates; information form Puerto Rico is receive on computer tapes
through the Vital Statistics Cooperative Program.
     Birth statistics presented in this report for years before 1951 and for
1955 are based on the total file of birth records.  Statistics for 1951-54,
1956-66, and 1968-71 are based on 50-percent samples, with the exception of
data for Guam and the Virgin Islands, which are based on all records filed.
During the processing of the 1967 data, the sampling rate was reduced from 50
to 20 percent.  For details of this procedure and its consequences for the
1967 data, see Vital Statistics of the United States, 1967, volume I, pages
3-9 to 3-11. From 1972 to 1984, statistics are based on all records filed in
the States submitting computer tapes and on a 50-percent sample of records in
all other States.  For Puerto Rico beginning in 1977, statistics are based on
all records filed.
     Information for years prior to 1970 for Puerto Rico, the Virgin Islands,
and Guam is published in the annual vital statistics reports of the Department
of Health of the Commonwealth of Puerto Rico, the Department of Public Health
of the Virgin Islands, the Department of Public Health and Social Services of
the Government of Guam, and in selected Vital Statistics of the United States
annual reports.
     U.S. natality data are limited to births occurring within the United
States, including those occurring to U.S. residents and nonresidents.  Births
to nonresidents of the United States have been excluded from all tabulations
by place of residence beginning in 1970.  (See "Classification by occurrence
and residence" for further discussion.)  Births occurring to U.S. citizens
outside the United States are not included in any tabulations in this report.
Similarly, the data for Puerto Rico, the Virgin Islands, and Guam are limited
to births registered in these areas.
     
Standard Certificate of Live Birth

     The U.S. Standard Certificate of Live Birth, issued by the Public Health
Service, has served for many years as the principal means of attaining
uniformity in the content of the documents used to collect information on
births in the United States.  It has been modified in each State to the extent
required by the particular State's vital statistics law.  However, most State
certificates conform closely in content to the standard certificate.
     The first standard certificate of birth was developed in 1900.  Since
then it has been revised periodically by the national vital statistics agency
through consultation with State health officers and registrars; Federal
agencies concerned with vital statistics; national, State, and county medical

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societies; and others working in the fields of public health, social welfare,
demography, and insurance.  This procedure has assured careful evaluation of
each item for its current and future usefulness for legal, medical,
demographic, and research purposes.  New items have been added when necessary,
and old items have been modified to ensure better reporting, or, in some
cases, dropped when their usefulness appeared to be limited.
     1978 revision-Effective January 1, 1978, a revised U.S. Standard
Certificate of Live Birth replaced the 1968 revision.  Changes on
the 1978 standard certificate include a new item on 1- and 5-minute Apgar
scores, the deletion of the item on birth injuries, and revision of the items
on legitimacy status and previous pregnancies.
     The item on legitimacy status was changed to read "Is mother married"
This is now a factual piece of information about the mother rather than an
attribute ascribed to the child, and the person completing the record does not
have the responsibility for making what may be a legal determination.
     The item on previous deliveries was changed to pregnancy history and
expanded to include two categories of fetal loss:  before and after 20
completed weeks of gestation.  This change provides information on two groups
that are of interest in medical research and emphasizes the fact that all
previous fetal losses should be included, both spontaneous and induced,
regardless of length of gestation.  For further discussion, see individual
sections for each item.
































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