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National Health Interview Survey (NHIS)
Public-Use Data Files

bullet graphicSurvey description
bullet graphicData file description
bullet graphicList of data file variables at a glance
bullet graphicData file technical characteristics
bullet graphicGeographic coverage
bullet graphicData availability
bullet graphicOrdering information
bullet graphicDocumentation contents
bullet graphicRelated reports
bullet graphicContact
bullet graphicNHIS Web Page 

Survey description
The National Health Interview Survey (NHIS) is a continuing nationwide survey of the U.S. civilian noninstitutionalized population conducted in households. Each week a probability sample of households is interviewed by trained personnel of the U.S. Bureau of the Census to obtain information about the health and other characteristics of each living member of the sample household. During a year, the sample is composed of 36,000 to 47,000 households, including 92,000 to 125,000 persons, depending upon the year. Information is obtained on the number of restricted-activity days, bed days, work- or school-loss days, and all physician visits occurring during the 2-week period prior to the week of the interview. Data are also obtained on the acute and chronic conditions that were responsible for these days or visits. Respondents are asked about long-term limitation of activity and the chronic conditions related to this disability. All conditions are coded according to the Health Interview Survey Medical Coding Manual and Short Index, a modified version of the International Classification of Diseases, using the limited diagnostic detail available from a household respondent. Data are obtained on all hospital episodes during the prior 12 months, including length of stay and whether surgery was performed. 

Data file description
There are five possible record types, each containing data on a particular topic: household characteristics,  person characteristics, health conditions, doctor visits, and hospital stays. Selected items from the person and household records are also included on each of the other record types. The records are arranged in five files. 

General list of variables by files

Household
Household ID number
Type of  living quarters
Telephone in home
Interview type
Date of completion
Size of family
Region
Type of PSU
Type of MSA

Person
Person ID number
Demographic variables
Sex
Age
Month and year of birth
Main racial background
Hispanic origin (1978-94 only)
Marital status
Veteran status
Education of:
 Individual
 Family head or reference person
Family income
Family relationships
Family size
Born in the United States, number of years lived in
 State of present residence (1989-94 only)
Foreign-born, number of years lived in the United
 States (1989-94 only)
Employment status
Class of worker
Industry
Occupation
Region
Respondent (self or proxy)
Height
Weight

Health and utilization variables
Limitation of activity
Self-assessed health status (1972-95 only)
Restricted-activity days
Bed days
Work-loss days
School-loss days
Doctor visits
Hospital days
Bed days in 12 months (1977-95 only)
Doctor visits:
 In the past 12 months
 Interval since last visit
Hospitalization:
 Number of episodes
 Days in past 12 months

Condition
ID number
Same demographic variables as in Person Record
Conditions list assigned:
 Musculoskeletal-skin
   Impairments
   Digestive
   Miscellaneous
   Circulatory
 Respiratory
Condition codes
For all conditions:
 Chronic or acute code
 Onset
 Whether doctor seen
 Last seen by doctor
 Related restricted-activity days:
 Bed days
 Work- or school-loss days
 Hospitalized
 Condition status
 Limitation of activity due to chronic conditions:
 Overall limitation status
 Limitation in ability to work (1983-95 only)
Injuries:
 Motor vehicle involved
 Place of accident

Doctor visit
ID number
Same demographic variables as in Person Record
Date of visit
Place of visit
Type of doctor
Conditions causing visit
Operations performed (1982-95 only)

Hospital
ID number
Same demographic variables as in Person Record
Type of service
Hospital ownership
Date of admission
Date of discharge
Number of nights in hospital
Operation performed
Hospitalization for delivery (1984-95 only)

NOTES: MSA is metropolitan statistical area. SMSA is standard metropolitan statistical area. ID is identification.

Data file technical characteristics
The block size and record length pertain to data stored on tape. The CD-ROM format comes with Statistical Export and Tabulation System (SETS) retrieval software. 

Data 
year
Record
length
Block
size
House-
hold
Person Condi-
tion
Visits Hospital
1996 360 32,760 25,990 63,402 44,357 14,024 6,103
1995 335 31,825 41,824 102,467 75,701 22,721 10,120
1994 335 31,825 48,584 116,179 89,199 27,811 11,811
1993 335 31,825 44,978 109,671 84,757 25,815 11,098
1992 335 3,350 51,643 128,412 97,630 29,215 13,111
1991 335 3,350 48,853 120,032 88,074 26,559 12,261
1990 335 3,350 48,860 119,631 92,534 25,312 12,524
1989 335 3,350 48,054 116,929 83,548 24,340 12,481
1988 335 3,350 50,061 122,310 88,345 25,541 13,580
1987 335 3,350 49,569 122,859 88,599 25,514 13,814
1986 335 3,350 24,698 62,052 45,106 12,833 7,074
1985 335 3,350 36,399 91,531 65,806 18,408 11,079
1984 335 3,350 41,471 105,290 75,260 20,515 13,515
1983 335 3,350 40,912 105,620 75,388 20,579 14,145
1982 335 3,350 39,988 103,923 72,340 20,505 14,022
1981 469 4,690 41,265 107,480 76,643 19,070 14,227
1980 480 4,800 39,226 102,629 74,182 18,764 13,863
1979 466 4,660 41,883 110,530 59,629 20,092 14,606
1978 516 5,160 41,164 109,940 57,517 20,100 14,583
1977 516 5,160 41,277 111,279 63,371 20,637 14,829
1976 480 4,800 41,559 113,178 58,346 21,550 15,239
1975 464 4,640 41,649 116,289 51,507 22,522 15,650
1974 478 4,780 41,314 116,287 37,453 15,692 22,058
1973 464 4,640 42,135 120,493 51,401 23,169 16,140
1972 464 4,640 46,149 132,891 63,714 100,245 17,553
1971 486 4,860 45,422 134,502 68,441 25,393 17,714
1970 516 5,160 39,011 116,466 68,331 21,412 16,073
1969 320 3,200 44,110 131,575 91,295 22,437 18,023

Geographic coverage
Each person's region of residence (four census categories) is shown.  The SMSA is identified in data years 1969-84 if the sample person lived in one of the larger standard metropolitan statistical areas (SMSAs) that was selected for the sample with certainty.

Data availability
NHIS data are collected annually. Data tapes are available for individual years from 1969-96. Data on CD-ROM are available from 1987-97.  ASCII files for 1995-97 are available on CD-ROM directly from from NCHS.  The 1997 data files and documentation are also available on the CDC/FTP Server.  An errata for the 1982-94 Condition files can be downloaded from the CDC/FTP server.

In addition to the data files already described, tapes containing data collected in special supplements (Current Health Topics) to NHIS are available directly from the National Center for Health Statistics. The CD-ROMs for 1987-97 contain most of the topics collected for each data year.  Data for the 1994 Income file can be downloaded from the CDC/FTP Server.

A longitudinal component of the NHIS is available on CD-ROM for 1986-94. 

NHIS State Data files have been constructed to allow for the production of direct State estimates. 

Ordering information
NHIS data tapes can only be purchased through the National Technical Information Service (NTIS). The CD-ROM can be purchased from NTIS and the Government Printing Office (GPO). The NTIS and GPO order numbers are as follows: 

Data on tape 

Data year NTIS order no. Price 
1996 PB98-502959 $305.00
1995 PB98-500432 742.00
1994 PB96-501721 742.00
1993 PB95-502241 742.00
1992 PB94-500915 742.00
1991 PB93-500700 742.00
1990 PB92-501170 1,029.00
1989 PB91-506279 1,029.00
1988 PB90-501180 1,029.00
1987 PB89-140651 1,029.00
1986 PB88-146139 891.00
1985 PB87-148144 1,029.00
1984 PB87-121547 1,029.00
1983 PB86-138856 1,029.00
1982 PB85-236172 891.00
1981 PB84-111657 1,029.00
1980 PB83-248922 1,029.00
1979 PB82-157173 1,029.00
1978 PB81-179285 1,029.00
1977 PB80-203953 1,029.00
1976 PB-300423 1,029.00
1975 PB-281126 1,029.00
1974 PB-285517 1,029.00
1973 PB-285511 1,029.00
1972 PB-285460 1,025.00
1971 PB-238524 1,029.00
1970 PB-237322 1,029.00
1969 PB-235543 1,029.00

 Data on CD-ROM 

Data 
year
NTIS order no. Price GPO order 
no.
Price
1997 ContactNCHS      
1996 PB99-501793 $69.00 017-022-01457-2 $16.00
1995 PB99-501785 69.00 017-022-01456-4 16.00
1994 PB97-501530 60.00 017-022-01368-1 21.00
1993 PB96-502240 60.00 017-022-01333-9 16.00
1992 PB95-502506 30.00 017-022-01368-1 15.00
1991 PB94-501236 30.00 017-022-01228-6 16.00
1990 PB94-501228 30.00 017-022-01227-8 16.00
1989 PB94-501244 30.00 017-022-01223-5 16.00
1988 PB94-501111 30.00 017-022-01282-1 15.00
1987 PB93-505931 30.00 017-022-01220-1 16.00

Documentation content
Each NHIS product contains the necessary documentation, which  includes tape content and technical information needed to access the data. Data stored on tape is accompanied by printed documentation. Documentation is available electronically on the CD-ROM.  Documentation for the 1997 data file is available on the CDC/FTP server.

Related reports
A detailed description of the survey and summary tables of the data are in the "Current Estimates" reports of the Vital and Health Statistics, Series 10. Data are also released in Advance Data reports. 

Contact
Divisio
n of Health Interview Statistics 
National Center for Health Statistics 
Centers for Disease Control and Prevention 
3311 Toledo Road, Room 2217 
Hyattsville, Maryland 20782-2003 
(301) 458-4001

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This page last reviewed September 09, 2008

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Disease Control and Prevention
National Center for Health Statistics
Hyattsville, MD
20782

1-800-232-4636