Integrated Health Interview Series

REVISED: Feb 20, 2009. The linking key variables NHISPID (for person level variables) and NHISHID (for household level variables) in the IHIS extract system are currently incorrect. We have identified and corrected the problem. However, the corrected NHISPID and NHISHID variables will not be available until the next IHIS data update.

In the interim, a simple coding fix for NHISPID can be implemented by users in their own IHIS data. For Stata users, adapt the following code for the years in your IHIS extract:

gen str16 test = "002006" + substr(nhispid,7,10) if year == 2006
  replace test = "002005" + substr(nhispid,7,10) if year == 2005
  replace test = "002004" + substr(nhispid,7,10) if year == 2004
  replace test = "002003" + substr(nhispid,7,10) if year == 2003
  replace test = "002002" + substr(nhispid,7,10) if year == 2002
  replace test = "002001" + substr(nhispid,7,10) if year == 2001
  replace test = "002000" + substr(nhispid,7,10) if year == 2000
  replace test = "001999" + substr(nhispid,7,10) if year == 1999
  replace test = "001998" + substr(nhispid,7,10) if year == 1998
  replace test = "001997" + substr(nhispid,7,10) if year == 1997
  replace test = "1996" + substr(nhispid,5,12) if year == 1996
  replace test = "1995" + substr(nhispid,5,12) if year == 1995
  replace test = "1994" + substr(nhispid,5,12) if year == 1994
  replace test = "1993" + substr(nhispid,5,12) if year == 1993
  replace test = "1992" + substr(nhispid,5,12) if year == 1992 & hispoversamp !=1
  replace test = "1991" + substr(nhispid,5,12) if year == 1992 & hispoversamp ==1
  replace test = "1991" + substr(nhispid,5,12) if year == 1991
  replace test = "1990" + substr(nhispid,5,12) if year == 1990
  replace test = "1989" + substr(nhispid,5,12) if year == 1989
  replace test = "1988" + substr(nhispid,5,12) if year == 1988
  replace test = "1987" + substr(nhispid,5,12) if year == 1987
  replace test = "1986" + substr(nhispid,5,12) if year == 1986
  replace test = "1985" + substr(nhispid,5,12) if year == 1985
  replace test = "1984" + substr(nhispid,5,12) if year == 1984
  replace test = "1983" + substr(nhispid,5,12) if year == 1983
  replace test = "1982" + substr(nhispid,5,12) if year == 1982
rename nhispid pidbad
rename test nhispid
sort nhispid

For SAS users, adapt the following code for the years in your IHIS extract:

data data2;
set data1;
format test $16.;
  if year=2006 then test="002006"||substr(nhispid,7,10);
  if year=2005 then test="002005"||substr(nhispid,7,10);
  if year=2004 then test="002004"||substr(nhispid,7,10);
  if year=2003 then test="002003"||substr(nhispid,7,10);
  if year=2002 then test="002002"||substr(nhispid,7,10);
  if year=2001 then test="002001"||substr(nhispid,7,10);
  if year=2000 then test="002000"||substr(nhispid,7,10);
  if year=1999 then test="001999"||substr(nhispid,7,10);
  if year=1998 then test="001998"||substr(nhispid,7,10);
  if year=1997 then test="001997"||substr(nhispid,7,10);
  if year=1996 then test="1996"||substr(nhispid,5,12);
  if year=1995 then test="1995"||substr(nhispid,5,12);
  if year=1994 then test="1994"||substr(nhispid,5,12);
  if year=1993 then test="1993"||substr(nhispid,5,12);
rename
  nhispid=pidbad
  test=nhispid;
run;

For additional information about merging variables from the original NHIS public use data files to IHIS data, please see the user note on merging.

Stata and SAS syntax files for merging variables from the original NHIS public use data files to IHIS data are being revised. Syntax files for 1969 to 1981 are currently unavailable.

In the next couple of weeks, new variables will begin to be added to the IHIS system. This will include new variables from the NHIS 2007 data released this summer, mortality variables from the NHIS-Linked Mortality Files, cancer screening, and cancer family history variables. We will also extend many of the current IHIS variables back in time.

On October 15 2008, IHIS introduced a new look to its website. This upgrade also included a significant redesign of the variable browsing and data extraction system. IHIS users now have more control over how they view the variables available, and they can now select variables from any point in the documentation system. The data extraction system also gives users more flexibility in how they select the years of data and variables they want to download.

Further information about the new browsing and data extraction options, in addition to general aspects of the data series, are available on the FAQ page.