Supplementary
Resources for National Health Interview Survey Public Use Files
With Variance Estimation Singleton PSUs - 2003, 2005, 2007
The public use file variance estimation structure for the
1997-present National Health Interview Survey (NHIS) almost
always provides 2 variance estimation primary sampling units
(PSU) for each variance estimation stratum. This page provides
supplementary resources for the small number of occurrences of
singleton PSUs in the 1997-present NHIS public use files.
Singleton PSUs occur in the
following public use files:
2003 Sample Child File (1
singleton PSU)
2005 Sample Child File (2)
2007 Sample Child File, 2007
Child Alternative Medicine File (2)
Some complex sample design
software packages (e.g., SUDAAN, Stata 10, R (including the
Survey add-on package)) have options available to compute
appropriate variance estimates when singleton PSUs are present.
Other complex sample design software packages (e.g., SPSS, Stata
9, SAS survey procedures) do not compute appropriate variance
estimates when singleton PSUs are present.
NCHS has created supplemental
files to enable users to compute appropriate variance estimates
with all contemporary complex sample design packages. It is not
necessary to use these supplemental files with SUDAAN, Stata 10,
or R, but the files can be used if a user chooses to do so.
Stata 9 will generate missing values for standard error
estimates if the supplemental files are not used, and SPSS and
the SAS survey procedures will produce standard error estimates
that are slightly smaller than they should be if the
supplemental files are not used.
2003 Sample Child File:
Supplemental file is available here.
Technical guidance is
available here.
2005 Sample Child File:
Supplemental file is available here.
Technical guidance is
available here.
2007 Sample Child File, 2007
Child Alternative Medicine File:
Supplemental files are available here.
Technical guidance is available here.
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