2001 NATIONAL HEALTH INTERVIEW SURVEY (NHIS) January 9, 2003 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. 2001 NHIS STRUCTURE Beginning with a new NHIS design in 1997, the NHIS contains "core questions" every year. The core questions are divided into three components which have then been divided into six questionnaires and then eight (2000-2001) or nine (1997-1999) data files. In some years, the NHIS will also have supplemental questions. The 2001 NHIS contains the core questions with added questions relevant to the Healthy People 2010 Objectives. Those added questions can be found in the Sample Adult and Sample Child files. See the Survey Description document for more details. The following chart shows the primary data files for the 2001 NHIS components: Core Component Questionnaire Data File ----------------- ------------- ---------------------- Family Core Household Household " Family Family " " Person " " Injury/Poison Episode " " Injury/Poison Verbatim Sample Adult Core Sample Adult Sample Adult* Sample Child Core Sample Child Sample Child* " Immunization Immunization -- Recontact -- * contains Healthy People 2010 Objectives supplemental questions 2001 NHIS FILES AND DOCUMENTATION The various files listed below comprise the 2001 National Health Interview Survey (NHIS) public use data release. A copy of this file (README.TXT), in ASCII format, is located with each of the following file groups (survey questionnaires, data files, SAS and SPSS input statements, and documentation). 2001 NHIS SURVEY QUESTIONNAIRES, ETC. The 2001 NHIS is broken into six questionnaires - Household, Family, Sample Adult, Sample Child, Immunization, and Recontact. The questionnaires that are provided with the release of the 2001 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. 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 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/readstep.html File --File Size-- File Name Description Format (KB) (Pages) QHOUSHLD.PDF Household Questionnaire PDF 110 18 QFAMILYX.PDF Family Core Questionnaire PDF 573 89 QSAMADLT.PDF Sample Adult Core Questionnaire PDF 292 45 QSAMCHLD.PDF Sample Child Core Questionnaire PDF 134 19 QIMMUNIZ.PDF Immunization Questionnaire PDF 218 24 QRECONCT.PDF Recontact Questionnaire PDF 51 6 FLASHCRD.PDF Flashcards PDF 757 167 FRMANUAL.PDF FR Manual PDF 1,696 345 NHISFLOW.PDF NHIS System Flow Chart PDF 46 1 The survey questionnaires, flashcards, and flow chart, and Field Representative Manual are located at: ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Survey_Questionnaire s/NHIS/2001 2001 NHIS DATA FILES The 2001 NHIS has been divided into eight data files. For ease of transmission, each of the 2001 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 NHIS2001. To do this, create a directory on your C: drive called NHIS2001. Then, using your browser, go to the FTP site containing the 2001 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:\nhis2001\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 NHIS2001 and do the following: - From DOS - in the c:\nhis2001 directory, type HOUSEHLD and hit Enter - From Windows - Double-click on HOUSEHLD.EXE or Click the Start Button, Click Run, enter c:\nhis2001\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 2001 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 Size ----- File Compressed Original File Name Description Format (KB) (KB) FAMILYXX.EXE Family Data ASCII 1,229 8,090 HOUSEHLD.EXE Household Data ASCII 470 2,610 IMMUNIZE.EXE Immunization Data ASCII 656 9,700 INJPOIEP.EXE Injury/Poison Episode ASCII 52 316 INJVERBT.EXE Injury/Poison Verbatim ASCII 93 825 PERSONSX.EXE Person Data ASCII 4,988 80,669 SAMADULT.EXE Sample Adult Data ASCII 3,440 27,715 SAMCHILD.EXE Sample Child Data ASCII 600 3,103 The 2001 NHIS data files are located at: ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Datasets/NHIS/2001 2001 NHIS SAS AND SPSS INPUT STATEMENTS Sample SAS and SPSS input statement programs have been provided for each data file. By using the ASCII data files (.DAT files) as input to these programs, SAS and SPSS data files can be created. The SAS and SPSS input statement programs are stored in ASCII format. File File Size File Name Description Format (KB) FAMILYXX.SAS Family SAS program ASCII 23 HOUSEHLD.SAS Household SAS program ASCII 9 IMMUNIZE.SAS Immunization SAS program ASCII 51 INJPOIEP.SAS Injury/Poison Episode SAS program ASCII 25 INJVERBT.SAS Injury/Poison Verbatim SAS program ASCII 4 PERSONSX.SAS Person SAS program ASCII 102 SAMADULT.SAS Sample Adult SAS program ASCII 111 SAMCHILD.SAS Sample Child SAS program ASCII 42 FAMILYXX.SPS Family SPSS program ASCII 20 HOUSEHLD.SPS Household SPSS program ASCII 6 IMMUNIZE.SPS Immunization SPSS program ASCII 85 INJPOIEP.SPS Injury/Poison Episode SPSS program ASCII 24 INJVERBT.SPS Injury/Poison Verbatim SPSS pgm ASCII 3 PERSONSX.SPS Person SPSS program ASCII 151 SAMADULT.SPS Sample Adult SPSS program ASCII 153 SAMCHILD.SPS Sample Child SPSS program ASCII 46 The 2001 NHIS sample SAS and SPSS input statement programs are located at: ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Program_Code/NHIS/20 01 2001 NHIS DOCUMENTATION FILES There is a data file layout (also called data dictionary) associated with each data file. There is also a Survey Description document which contains general information about the 2001 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/readstep.html File --File Size-- File Name Description Format (KB) (Pages) FAMILYXX.PDF Family File Layout PDF 458 101 HOUSEHLD.PDF Household File Layout PDF 86 16 IMMUNIZE.PDF Immunization File Layout PDF 627 111 INJPOIEP.PDF Inj/Poi Episode File Layout PDF 430 82 INJVERBT.PDF Inj/Poi Verbatim File Layout PDF 43 9 PERSONSX.PDF Person File Layout PDF 3,041 532 SAMADULT.PDF Sample Adult File Layout PDF 3,138 506 SAMCHILD.PDF Sample Child File Layout PDF 893 149 SRVYDESC.PDF Survey Description Document PDF 481 91 The 2001 NHIS documentation files are located at: ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentatio n/NHIS/2001 2001 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 the Family Serial Number (FMX) within the Household Serial Number (HHX). The person-level files (Person, Sample Adult, Sample Child, and Immunization) have been sorted by the Person Number (PX) within the Household Serial Number (HHX). The injury files (Injury/Poison Episode and Injury/Poison Verbatim) have been sorted by Person Number (PX) and Injury/Poison Episode Number (IPEPNO) within the Household Serial Number (HHX). MERGING 2001 NHIS DATA FILES To merge data from the Household file into the Family file, into any of the person-level files (Person, Sample Adult, Sample Child, and Immunization) or into any of the episode-level files (Injury/Poison Episode and Injury/Poison Verbatim), merge by variable HHX. To merge any person-level file with another person-level file or with an episode-level file, merge by variables HHX and PX. To merge one Injury file with the other Injury file, merge by variables HHX, PX, and IPEPNO. To merge the Family file information into a person-level or episode- level file, re-sort the person-level or episode-level file by variables HHX and FMX and then merge by HHX and FMX. CONTACT INFORMATION Updates about new data releases, publications, or errors will be sent to members of the NHIS Listserv. To join, visit the CDC website at: http://www.cdc.gov/subscribe.html Input your name and E-mail address, select the item "National Health Interview Survey (NHIS) researchers", and click the "Subscribe" button. 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.