Archived IHIS News
September 2015: New data-2014 imputed income files, updated 2014 injury files, 2004-2010 corrected child birth weights, 500+ variables from historical supplements including immunization data
IHIS has integrated the 2014 imputed income files and the re-released 2014 injury/poisoning file from NCHS. The re-released injury/poisoning data now include ICD-9 and external cause codes AND changes to other variables affecting frequencies; these changes to episode-level data cascade to affect person-level variables. Users who created an extract using 2014 person-level or episode-level injury data prior to September 23, 2015 should be advised that the data have changed and the current IHIS version reflects the most recent NCHS release of the injury/poisoning episode file released on September 9, 2015.
The release also includes NHIS-corrected birth weight files for sample children in 2004-2010. 2014 survey text is now available, allowing users to easily access the original survey questions associated with integrated IHIS variables. Variables from the following historical supplements are now included in the IHIS database:
IHIS now offers most variables from the 2014 NHIS, including measures of health care access, health behaviors, disability and conditions, core demographics, injury and poisoning episodes, and socioeconomic indicators.
June 2015: 1986-2009 linked mortality files now available through IHIS. Harmonized industry and occupation variables added.
IHIS now includes the updated mortality files. Variables from these files allow users to link 1986-2009 integrated NHIS survey data with death certificate information from the National Death Index through December 2011. Combining these two data sources allows for statistical analyses of the relationship between mortality and the rich array of socio-demographic characteristics, health factors, and health care access information available in the NHIS data.
Additionally, the release offers newly IHIS created industry and occupation variables harmonized from 1969 to the present, allowing IHIS users to make comparisons of consistent categories over time. The original detailed industry and occupation codes are also now available in the same variables over time (IND and OCC), making it easier for users to include all relevant information in their extracts. For more information, please see the IHIS user note on how the industry and occupation variables were constructed.
The release also integrates the 1997-1999 injury and poisoning records and historical supplements for hearing, vision, asthma, unintentional injuries, as well as pregnancy and smoking.
IHIS is also debuting its data brief series, a set of concise research reports that highlight unique aspects of the IHIS database and interesting research topics that can be investigated using the data. Brief 01: Multigenerational Families and Food Insecurity in the United States, 1998-2013.
April 2015: Release of historic 1990-1996 imputed income files, and over 2000 fully integrated CAM variables from 2012
The release also introduces imputed income data for 1990-1996. While these differ in structure from the 1997-forward imputed income files, they can be used to fill in missing income data for all persons in the 1990-1996 samples. Over 2000 variables from the complementary and alternative medicine (CAM) supplements for sample adults and sample children have been fully integrated into the IHIS data for the 2012 sample. A change in the structure of the CAM questionnaire makes it difficult to compare original NHIS CAM data from 2012 with previous samples; the newly released IHIS data include the original variables released by NHIS in 2012 as well as variables constructed through special programming that are comparable to CAM variables released by the NHIS in previous years to allow for easier analysis of these variables over time. The release also includes a series of variables rom the 2002 survey on barriers to community participation. Finally, historic child development and child medication variables from the 1981 child health supplement are now available through the IHIS.
March 2015: Release of remaining 2013 supplements, historic AIDS testing variables, full documentation on all variables, and NHIS linking keys
The 2013 supplements not included in the October 2014 IHIS data release have been integrated. These include 2013 variables on asthma, cancer screening, health care access and utilization, disability, epilepsy, food security, heart disease and stroke prevention, hepatitis, immunization, immunosuppression, internet access and email usage, mental health, mental health services, and tobacco. IHIS is also releasing a series of historic variables with information about HIV/AIDS testing; these include variables on reasons for being tested, reasons for not being tested, locations of testing, information about testing, and discussion of test results. Additionally, this release provides full documentation for an additional 1,250 variables on topics including exercise, weight control, chronic mental illness, colon cancer testing, insurance, public health service tests, quitting smoking, mammograms, Pap testing, hypertension, income, and HIV/AIDS information and testing. All integrated IHIS variables now have full documentation, including a description of the variable, an overview of the codes, universe information, and a discussion about comparability of the variable over time. Survey text is now available for integrated 2012 and 2013 IHIS variables. Additionally, the original NHIS person-level linking keys (HHX, FMX, and PX) for the 1997-forward samples and day of interview (INTERVWDAY) for the 1970-1996 samples are now available.
The latest IHIS data release includes injury-level records available through hierarchical extracts, as well as imputed income variables for 2013, and full documentation for an additional 1250 variables. Check back for the release of additional 2013 data later this year.
The latest IHIS data release includes most variables from the newly released 2013 data, including measures of health care access, health behaviors, disability and conditions, core demographics, and socioeconomic indicators. Check back for the release of additional 2013 data later this year.
June 2014: New data release includes 2000-2012 injury and poisoning records, and streamlined food frequency variables
The latest IHIS data release includes data from the 2000-2012 injury and poisoning episode files. IHIS has created person-level variables that are harmonized with person-level injury variables available in 1997-1999. These variables are now available through the IHIS data extract system.
IHIS has revised the extensive list of food frequency variables and is releasing new food frequency variables that allow for greater comparability across samples. For more details on these changes, see the new IHIS Revisions and Errata web page. The Revisions and Errata page allows users to track changes and improvements to IHIS data by noting changes to the data including new and updated variables, eliminated variables, and any corrections.
Additionally, this data release provides updated variable-level information pages for an additional 1,000 existing variables. Topics covered by these fully documented variables include: breast exams, child schooling, cancer knowledge, diabetes, firearms, food knowledge, health information sources, radon, and vaccinations.
The latest IHIS data release added approximately 600 variables, including new variables for the 2012 supplements. New or expanded supplements in 2012 that are now part of IHIS include: child balance; complementary and alternative medicine; enhanced questions on health care access and utilization; food security, child mental health and mental health services; tobacco; voice, speech, and language; heart disease and stroke prevention; as well as internet and email usage. IHIS has also provided new or updated variable-level information pages for an additional 500 existing variables.
The latest IHIS data release has added variables from the 2012 NHIS sample, including the imputed income variables. The 2012 survey continues to include variables used to monitor the Affordable Care Act (see brief at user note for more information on these variables).
In 2012, the NHIS included a Complementary and Alternative Medicine (CAM) Supplement for sample adults and sample children. This collected information for all sample children age 4 and over and sample adults age 18 and over on their use of and payment for 18 kinds of CAM. Information includes recency of use (in the past 12 months), frequency of use, and insurance coverage and out-of-pocket and additional expenses related to CAM. While these questions are similar to the CAM Supplements that were fielded in 2002 (sample adults only) and 2007, not all content is comparable to earlier versions. The 2012 survey also included new questions on CAM in quarters two through four. This data release provides a subset of the 2012 CAM variables and the remainder will be made available in a future data release.
This data release also contains the Child and Adult Disability questions, first included for half the sample persons in the 2010 Quality of Life Supplement and continued in the 2011 Adult Functioning and Disability Supplement. In 2012, several new questions were added to the disability file Functioning and Disability (AFD) section that are similar to the 2010 and 2011 variables, but have minor changes in the universe. These new variables, reflecting the different contexts or universes relative to 2011 and 2010, are forthcoming.
In addition, other new variables from the 2012 NHIS are forthcoming. These include questions from the Adult and Child Voice, Speech and Language Supplements, the Child Balance Supplement, the Adult Internet and Email Usage Section, six new supplemental questions on the use of tobacco products other than cigarettes, and two new supplemental questions about flu shots before, during, or after pregnancy.
IHIS also has provided new or updated variable-level information pages for existing variables collected in various years between 1970 and 2012.
Feb 2012: Remaining 2011 data released, Monitoring the ACA, Pre-1997 conditions variables released, Imputed income variables released
The latest IHIS data release has added the remaining 2011 data that was not released by IHIS in August 2012. New topics covered in 2011 include service in the armed forces; reasons for not having a usual source of care; steps taken in the past year to save money on medical care; most recent ER visit; last health care visit; long-term care insurance; health insurance coverage in the past 3 years; and treatment of children's mental health.
Beginning with the 2011 NHIS, around 85 new questions were added to the NHIS that were designed to monitor the implementation of the Affordable Care Act (ACA). IHIS has created a user note on these variables, and SHADAC has released a brief on the variables.
IHIS now makes it much easier to work with the pre-1997 "condition records." Before 1997, information about health conditions was collected in the form on many-to-one condition records. This data structure made it difficult to analyze the condition records in concert with othere IHIS/NHIS data that treat the person or household as the unit of analysis. IHIS staff have solved this problem by converting the pre-1997 condition records into person-level data. Users can now analyze chronic conditions such as asthma, diabetes, hypertension, and breast cancer over a longer time series than was previously available. For more information, consult the IHIS user note.
The IHIS staff has created new variables that reflect the ratio of imputed income to the federal poverty guidelines. (Note: The federal poverty guidelines are different from the federal poverty thresholds. See here for information on the difference.) These variables (POVIMPHHS1 through POVIMPHHS5) cover 2009-2011 and are constructed from imputed point estimates of income. Users should refer to the variable descriptions for these variables for links to NHIS documentation on appropriate use of variables with imputed data.
The latest IHIS data release has added data from 2011. New variable groups include health care access and utilization, food security, functioning and disability, and fitness center use.
IHIS now includes new summary insurance variables, indicating the type of coverage, the features of private plans, and the reasons for not having coverage, that are consistently coded for the 1980s to the present. Two new user notes, on changes in insurance data collection and the shifting definition of private insurance, are also now available, along with hundreds of other variables addressing various aspects of insurance coverage.
The variable SAMPWEIGHT is once again supplying the correct values.
The lastest IHIS data release has added data from 2010, includes material from the historical public use files from 1963 to 1968, and brings the number of integrated variables available through IHIS to approximately 12,000.
Users can now analyze IHIS data online, using high-speed tabulation software developed at UC-Berkeley. The online tabulator is especially useful for creating frequency and cross-tabulation tables, calculating means, and significance testing. Experienced data users may wish to use the tabulator to get quick or preliminary results before downloading a dataset. Users who do not have experience using a statistical package can now answer simple research questions by creating tables online. In introductory classes on statistics or public health, students can use the tabulator to formulate and test hypotheses about public health trends and differentials, getting results within seconds. A detailed user note provides explanations and examples of how to analyze IHIS data on-line.
The latest IHIS data release increased the number of variables to over 7000. New variable groups include adult and child use of vitamins and herbs, falls and balance problems, hearing and vision problems, and use of aids to mobility. Also newly available is a weight (MORTWTSA) suitable for use with variables from the sample adult files in conjunction with variables on survey participants' mortality and cause of death.
The latest IHIS data release added data from 2007, 2008, and 2009 and increased the number of variables to over 5000. New variable groups include adult and child mental health, cancer family history, use of complementary and alternative medicine, health knowledge, adult leisure-time physical activity, imputed income and earnings, HPV immunization, and mortality and cause of death of survey participants.
The BMICALC (IHIS-calculated Body Mass Index), which was created by programming, initially included some incorrect values for 1982-1995 due to an error in the programming statements. Respondents with unknown values for height were included in the BMI calculation, which yielded artificially low values. The version of BMICALC available as of August 16, 2010 no longer includes those incorrect values. Researchers who used the BMICALC variable for 1982-1995 prior to August 16, 2010 should redo their analyses using the corrected version of the variable.
The original versions of the linking key variables NHISPID (for person-level variables) and NHISHID (for household-level variables) were incorrect. A coding fix for NHISPID was posted in IHIS news on January 27, 2009. The versions of NHISPID and NHISHID available as of August 16, 2010 are correct, and the coding fix is no longer needed.
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
For SAS users, adapt the following code for the years in your IHIS extract:
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);
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.