Data Suppression
Data
Source:
National Center for Health Statistics (NCHS), National
Vital Statistics System (NVSS)
Infant mortality records are identified from the NCHS
mortality source data where the NCHS source data element
[Age Recode 12] is equal to 01 (Under 1 year (includes
not stated infant ages)).
The
Birth and Infant Mortality Statistics data are composed
of two types of information: aggregated event data
and rate data. The event data is aggregated over a
five year period from the Birth and Infant Mortality
Statistics data provided by NCHS using the data suppression
rules listed below. Rate data is calculated by taking
the aggregated event data for the county or state
and dividing that number by the total number of births
for the county or state for the same five year period.
That result is multiplied by 1000.
The
Birth and Infant Mortality Statistics data are aggregated
at two levels: state and county. The geography to
which a record is assigned is based on the state residence
FIPS code and the county residence FIPS code as identified
in the NCHS data. The suppression rules are applied
to each data set separately. This means that data
that is suppressed at the county level may not be
suppressed at the state level.
Each
input data set from NCHS contains data for one full
year. There is a three (3) year lag in the release
of new data (e.g. the 2002 data became available in
2005). Data for any specific state or county may not
appear in each of the five (5) years of NCHS input
data. The HGDW only reports data for states and counties
where the state or county is included in all five
years of the input data.
The
following US Territories do not report health statistical
data to the NCHS so they are not represented in the
HGDW for Birth and Infant Mortality Statistics data:
Federated
States of Micronesia
Marshall Islands
Republic of Palau
US Minor Islands
The
Birth and Infant Mortality Statistics data reported
in the HGDW follows the NCHS rules as set forth in
the data use agreement between HRSA and NCHS. These
rules apply to the data for any single state or county.
Data
are not reported when any one of the following
conditions
is met:
- NCHS
data state FIPS code is not a valid state FIPS
code
- NCHS
data state FIPS code and county FIPS code combination
is not a valid state FIPS code and county FIPS
code combination
Data are reported as blank (null) when any of the
following conditions is met:
- For
natality aggregations: where there are not 5 years
of natality event data.
- For
mortality aggregations: where there are not 5 years
of mortality event data.
- For
all rates: where the Total Live Births is null (blank)
or zero (0).
- For
specific rates: where the numerator is null (blank).
Data
are reported as suppressed (-999) when any of the
following conditions are met:
- For
aggregated values: where the value for the 5 year
period is one (1) or two (2).
- For
aggregated values: where the data element could
be used to calculate a related value that has been
suppressed.
- For
aggregated values: where any member of a set of
related data elements is suppressed (e.g. suppressing
any single combination of gender and race causes
all combinations of gender and race to be suppressed
for a record).
- For
all rates: where the Total Live Births is suppressed
(-999).
- For
specific rates: where the numerator is suppressed
(-999).
See
the Infant Mortality
Suppression Application Table and the Live
Birth (Natality) Suppression Application Table
for clarification of the rules of data suppression
where the data element that is at the same level or
a lower level of aggregation than a data element that
has been suppressed.
Data
are reported as zero (0) when either of the following
conditions is met:
- value
is zero (0).
- there
are mortality records (all deaths, not limited to
infant deaths) for each of the five years but there
are no infant mortality events.
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