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National Health Interview 

Survey

Patricia Barnes, M.A.

Using the 1997 and 1998 Injury

and Poisoning Data Files

CCENTERS FOR DISEASE CONTROL

AND PREVENTION DC

The Focus of the Injury and 

Poisoning Data

Prior to 1995: 

Beginning in 1997:

Conditions

Episodes 
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Location of Injury and 

Poisoning Data

1995: Condition file

1997:

Injury Episode file

Injury Verbatim file

Poison Episode file

Person file

Episode Based Files

Injury Episode file

Injury Verbatim file

Poison Episode file

A person will appear in these 

files as many times as 

he/she has unique episodes
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Person Based File

Person file

A person will appear only one 

time in this file

Where to Find Injury and 

Poisoning Data

www.cdc.gov/nchs/nhis.htm

1997

CD Rom

1998

www.cdc.gov/nchs/nhis.htm
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How Do I Get the Data?

Downloading Data from 

Website

Create subdirectory called

NHIS1997 for 1997 data and 

NHIS1998 for 1998 data on 

hard drive

Download file from FTP site to 

subdirectory
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Extracting the .EXE File

From DOS – Type file 

name without .EXE 

extension

From Windows – double 

click on file

1997 NHIS CD Rom

Files are in ASCII format

Files can be read directly 

from CD Rom
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How Do I Get the ASCII Files 

into a Stats. Software 

package?

Reading in the Data

SAS Programs

File name.sas

SPSS Programs

File name.sps
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SAS/SPSS Programs

Website: download and 

save programs to

hard drive

CD Rom: read programs 

directly from CD Rom

INJEPSOD.SAS Results

ASCII converted to SAS

Variable and value labels

Contents procedure of file

Weighted and unweighted 

frequency counts of 

variable record type
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How Do I Put the Data 

Together?

Concatenating Injury and 

Poisoning Episode Files

Injury Poisoning +

Injury

Poisoning

= Missing Data, Questions not found in both files
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Merging Injury/Poisoning 

Episode File and Person File

+ Person

Injury

Poisoning

= Missing Data, Questions not found in both files

Merged Injury/Poisoning 

Episode File and Person File

Injury

Poisoning

Person

= Missing Data, Questions not found in all files
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Things to Know About the 

Files: Those Little Quirks

Calculating Annual Estimates

(variable)(4)(WTFA) = Annual 

Estimate of Variable

Annual estimates of episodes 

and conditions can be made

Annual estimates of the 

number of persons injured 

can NOT be made due to the 

3 month reference period
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Injury and Poisoning 

Episode Files:

Variance Estimation

Design information from the 

entire sample must be used 

in variance estimation

Design information is found in 

the Person file

Injury Episode File

Poisoning Episode File

Injury Verbatim File

Contain ONLY injury or 

poisoning information and 

unique identifiers

Must be linked to the Person file 

to obtain sociodemographic 

variables, design variables, etc.
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Injury Episode File

Contains a maximum of:

four injury episodes

four ICD-9-CM codes

three E codes

Contains nine poisoning 

episodes in 1997

Injury Episode File

ICD-9-CM code and E codes are 

based on information supplied 

by respondents, not medically 

trained personnel

Analysts should be cautioned 

against making estimates 

based on small numbers of 

observations
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Poisoning Episode File

Contains no ICD-9-CM codes or 

E codes

Contains episodes coded as 

“Allergic/adverse reaction to 

medical or other substance” 

or “Something else – NOT 

poisoning”

Injury Verbatim File

Edited only for confidentiality

Grammatical and/or spelling 

errors were not corrected

Analysts should be cautioned 

against making estimates 

based on small numbers of 

observations
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Injury Section – Person File

Contains summary information 

about injury and poisoning 

episodes

Annual estimates can only be 

made on variables INJCT, 

ICD9CT, and POICT