2006 NATIONAL HEALTH INTERVIEW SURVEY (NHIS) June 16, 2007 PUBLIC USE DATA RELEASE * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * WARNING - DATA USE RESTRICTIONS! Read Carefully Before Use The Public Health Service Act (Section 308 (d)) provides that the data collected by the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention (CDC), may be used only for the purpose of health statistical reporting and analysis. Any effort to determine the identity of any reported case is prohibited by this law. NCHS does all it can to assure that the identity of data subjects cannot be disclosed. All direct identifiers, as well as any characteristics that might lead to identification, are omitted from the data files. Any intentional identification or disclosure of a person or establishment violates the assurances of confidentiality given to the providers of the information. Therefore, users will: 1. Use the data in these data files for statistical reporting and analysis only. 2. Make no use of the identity of any person or establishment discovered inadvertently and advise the Director, NCHS, of any such discovery (301-458-4500). 3. Not link these data files with individually identifiable data from other NCHS or non-NCHS data files. By using these data, you signify your agreement to comply with the above-stated statutorily based requirements. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - INTRODUCTION The National Health Interview Survey (NHIS) is conducted annually by the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention (CDC). The NHIS administers face-to-face interviews in a nationally representative sample of households. Each week a probability sample of the civilian noninstitutionalized population of the United States is interviewed by personnel of the U.S. Bureau of the Census. Information is obtained about the health and other characteristics of each member of the household. 2006 NHIS STRUCTURE The NHIS contains many similar questions every year. The repeated items are called "core questions". Beginning with a new NHIS design in 1997, these core questions were divided into three components -- Family, Sample Adult, and Sample Child. In some years, the NHIS also has supplemental questions/modules. The 2006 NHIS contains the core questions and additional questions in the Sample Adult on the subject of stroke, diabetes, arthritis, and weight control. The 2006 NHIS files consist of five questionnaires and seven data files. See the Survey Description document for more details. The following chart shows the output data files for the 2006 NHIS components: Component Questionnaire Output Data File ----------------- ------------- ---------------------- Family Core Household Household " Family Family " " Person " " Injury/Poison Episode " " Injury/Poison Verbatim Sample Adult Core Adult Sample Adult Sample Child Core Child Sample Child -- Recontact -- 2006 NHIS FILES AND DOCUMENTATION The various files listed below comprise the 2006 National Health Interview Survey (NHIS) public use data release. 2006 NHIS SURVEY QUESTIONNAIRES, ETC. The 2006 NHIS consists of five questionnaires - Household, Family, Adult, Child, and Recontact. The questionnaires that are provided with the release of the 2006 NHIS are not identical to the versions that were utilized in the field. The questionnaires provided here reflect the minor changes in data presentation that occurred during the editing process. Both English and Spanish versions of the questionnaires are released. The Spanish versions contain interviewer instructions in English. The 2006 NHIS has similar questions as previous years and the same software was utilized for the questionnaire delivery system as was used for the 2005 NHIS. Prior to 2004, one household equaled one "case". Beginning in 2004, each family is considered a separate case. For multiple-family households, there is a "parent" case designated for the first family identified, and each subsequent family becomes a "spawned" case from the parent, with its own unique case id. Flashcards were handed to the respondents to facilitate their ability to answer certain questions - these are referenced in the questionnaires. The Field Representative Manual contains the guidelines and instructions on the survey process and topic areas covered by the NHIS and was provided to the Field Representatives (also known as interviewers). Also included is a flowchart that shows how a respondent would move through the various questionnaires. The survey questionnaires, flashcards, and Field Representative Manual are in Adobe Portable Document Form (PDF) format and can be viewed with Adobe Acrobat software. The Adobe Acrobat Reader software can be downloaded from the Adobe Acrobat Web site at: http://www.adobe.com/prodindex/acrobat/readstep2.html 2006 NHIS DATA FILES The 2006 NHIS has been divided into seven data files. For ease of transmission, each of the 2006 NHIS data files has been converted into a self-extracting compressed format. To load and expand a compressed file into an ASCII file, perform the following steps: Download a compressed file onto your hard drive into an appropriate directory (folder). For example: Copy the data file HOUSEHLD.EXE into a directory called NHIS2006. To do this, create a directory on your C: drive called NHIS2006. Then, using your browser, go to the FTP site containing the 2006 NHIS data files (see address at end of this section). Right click on the HOUSEHLD.EXE file. Depending on your browser, select Save Link As... or Save Target As... Type c:\nhis2006\HOUSEHLD.EXE in the box labeled File Name and hit Enter. To then convert HOUSEHLD.EXE into the ASCII file HOUSEHLD.DAT, go to the directory NHIS2006 and do the following: - From DOS - in the c:\nhis2006 directory, type HOUSEHLD and hit Enter - From Windows - Double-click on HOUSEHLD.EXE or Click the Start Button, Click Run, enter c:\nhis2006\HOUSEHLD.EXE and hit Enter. The ASCII file HOUSEHLD.DAT will be generated which can then be used for processing by PC statistical software packages which utilize ASCII formatted input, or transferred to another computer for processing. NOTE: The 2006 NHIS files are large in size. Please use caution and check your disk drive capacity before extracting. NOTE: Users have encountered difficulties when downloading the data files onto their 'Desktop'. When downloading the data files, please use a separate folder (directory). File Name Description Format FAMILYXX.EXE Family Data Compressed ASCII HOUSEHLD.EXE Household Data Compressed ASCII INJPOIEP.EXE Injury/Poison Episode Compressed ASCII INJVERBT.EXE Injury/Poison Verbatim Compressed ASCII PERSONSX.EXE Person Data Compressed ASCII SAMADULT.EXE Sample Adult Data Compressed ASCII SAMCHILD.EXE Sample Child Data Compressed ASCII 2006 NHIS SAS, SPSS AND STATA INPUT STATEMENTS Sample SAS, SPSS, and STATA input statement programs have been provided for each data file. By using the ASCII data files (.DAT files that can be extracted from the .EXE files) as input to these programs, SAS, SPSS, or STATA data files can be created. The SAS, SPSS, and STATA input statement programs are stored in ASCII format. STATA programs were not provided prior to the 2002 data year. File Name Description Format FAMILYXX.SAS Family SAS program ASCII HOUSEHLD.SAS Household SAS program ASCII INJPOIEP.SAS Injury/Poison Episode SAS program ASCII INJVERBT.SAS Injury/Poison Verbatim SAS program ASCII PERSONSX.SAS Person SAS program ASCII SAMADULT.SAS Sample Adult SAS program ASCII SAMCHILD.SAS Sample Child SAS program ASCII FAMILYXX.SPS Family SPSS program ASCII HOUSEHLD.SPS Household SPSS program ASCII INJPOIEP.SPS Injury/Poison Episode SPSS program ASCII INJVERBT.SPS Injury/Poison Verbatim SPSS pgm ASCII PERSONSX.SPS Person SPSS program ASCII SAMADULT.SPS Sample Adult SPSS program ASCII SAMCHILD.SPS Sample Child SPSS program ASCII FAMILYXX.DO Family Stata program ASCII HOUSEHLD.DO Household Stata program ASCII INJPOIEP.DO Injury/Poison Episode Stata program ASCII INJVERBT.DO Injury/Poison Verbatim Stata pgm ASCII PERSONSX.DO Person Stata program ASCII SAMADULT.DO Sample Adult Stata program ASCII SAMCHILD.DO Sample Child Stata program ASCII 2006 NHIS DATA FILE DOCUMENTATION FILES There are three documentation files associated with each subject matter file (summary, layout, frequency report). There is also a Survey Description document which contains general information about the 2006 NHIS. The documentation files are in PDF format and can be viewed with Adobe Acrobat software. The Adobe Acrobat Reader software can be downloaded from the Adobe Acrobat Web site at: http://www.adobe.com/prodindex/acrobat/readstep2.html File Name Description Format FAMILYXX_SUMMARY.PDF Family File Variable Summary PDF HOUSEHLD_SUMMARY.PDF Household File Variable Summary PDF INJPOIEP_SUMMARY.PDF Inj/Poi Episode File Variable Summary PDF INJVERBT_SUMMARY.PDF Inj/Poi Verbatim File Variable Summary PDF PERSONSX_SUMMARY.PDF Person File Variable Summary PDF SAMADULT_SUMMARY.PDF Sample Adult File Variable Summary PDF SAMCHILD_SUMMARY.PDF Sample Child File Variable Summary PDF FAMILYXX_LAYOUT.PDF Family File Layout PDF HOUSEHLD_LAYOUT.PDF Household File Layout PDF INJPOIEP_LAYOUT.PDF Inj/Poi Episode File Layout PDF INJVERBT_LAYOUT.PDF Inj/Poi Verbatim File Layout PDF PERSONSX_LAYOUT.PDF Person File Layout PDF SAMADULT_LAYOUT.PDF Sample Adult File Layout PDF SAMCHILD_LAYOUT.PDF Sample Child File Layout PDF FAMILYXX_FREQ.PDF Family File Frequency Report PDF HOUSEHLD_FREQ.PDF Household File Frequency Report PDF INJPOIEP_FREQ.PDF Inj/Poi Episode File Frequency Report PDF INJVERBT_FREQ.PDF Inj/Poi Verbatim File Frequency Report PDF PERSONSX_FREQ.PDF Person File Frequency Report PDF SAMADULT_FREQ.PDF Sample Adult File Frequency Report PDF SAMCHILD_FREQ.PDF Sample Child File Frequency Report PDF SRVYDESC.PDF Survey Description Document PDF NOTE: The numeric portion of the variable labels included in the SAS programming code and frequency documents are provided as a link to the file layout document but do not necessarily link to the question numbers on the survey instrument, especially for recode variables. The recode variables may be based on more than one question or on other recodes. 2006 NHIS DATA FILES' RECORD SEQUENCE All records in the NHIS data files have first been sorted by the Household Serial Number (HHX). The Family file has been sorted by combining the Household Serial Number (HHX) and the Family Serial Number (FMX). The person-level files (Person, Sample Adult, and Sample Child) have been sorted by combining the Household Serial Number (HHX), Family Sequence Number (FMX) and Person Sequence Number (FPX). The injury files (Injury/Poison Episode and Injury/Poison Verbatim) have been sorted by combining the Household Serial Number (HHX), Family Sequence Number (FMX), Person Sequence Number (FPX), and Injury/Poison Sequence Number (IPEPNO). MERGING 2006 NHIS DATA FILES To merge data from the Household file into the Family file, or into any of the person-level files (Person, Sample Adult, or Sample Child) or into any of the episode-level files (Injury/Poison Episode and Injury/Poison Verbatim), merge by variable HHX. To merge the Family file information into a person-level or episode-level file merge by HHX and FMX. To merge any person-level file with another person-level file or with an episode-level file, merge by variables HHX, FMX and FPX. To merge one Injury file with the other Injury file, merge by variables HHX, FMX, FPX, and IPEPNO. NOTE: An asterisk in the summary and/or frequency documents means that there is additional information for the variable in the Notes section of the file's layout document. CONTACT INFORMATION Updates about new data releases, publications, or errors will be sent to members of the NHIS Listserv. To join, visit the website at: http://www.cdc.gov/nchs/about/major/nhis/nhislist.htm For additional information on NHIS data products: Phone : 301-458-4901 FAX : 301-458-4035 E-mail : nhislist@cdc.gov. Internet: http://www.cdc.gov/nchs/nhis.htm For additional information on other NCHS data products: Phone : 301-458-INFO [301-458-4636] E-mail : nchsquery@cdc.gov Internet: http://www.cdc.gov/nchs STATEMENT OF AUTHENTICITY This material has been cleared for public distribution by CDC/ATSDR and will be authentic if obtained directly from ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/. CDC/ATSDR takes all effort to assure the authenticity of electronically distributed documents. However, in all instances where the electronic and official agency record differ, the authenticity of the official agency record is controlling.