WLS Codebooks

Note: Codebooks contain frequency data from the private data release. For some variables, these differ from the frequencies in the public release. Variables that differ between the public and private versions include "(not available on public release)" as part of the variable description, or a note indicating the difference between the public and private versions.

National Death Index - Cause of Death

NDI Cause of Death Module


OVERVIEW 
    
In 2000 and 2006 WLS matched dead graduates to NDI's records. This
resulted in 1050 cases for which we have a cause of death. Similarily,
matching done in 2001 and 2007 for the selected sibling yielded 927
cases. Since then, these variables have been periodically updated by
matching all the known deaths to NDI records. System missing values
are assigned to all variables for cases that are not known to be
deceased.  Cases that are known to be deceased after our last NDI
update or those that could not find a match in the NDI records are
coded -4, not ascertained.

NDI has used different versions of ICD through out the years.  Years 1979-98
use ICD-9, and 1999-present use ICD-10. Thus, the variables in this module
are a combination of these coding schemes. Please use DEATYR to determine
which code set a particular case is using. Generally speaking, ICD-9 is
numeric and ICD-10 begins with a letter.

NDI describes the entity axis conditions as 'First, to facilitate etiological
studies of the relationships among conditions, it was necessary to reflect
accurately in coded form each condition and its location on the certification
in the exact manner given by the certifier.  Secondly, the codification
needed to be carried out in a manner by which the underlying cause-of-death
could be assigned through computer applications.  The approach was to suspend
the linkage provisions of the ICD for the purpose of condition coding and
code each entity with minimum regard to other conditions present on the
certification.'

NDI describes the record axis condition as 'Essentially, the axis of
classification is converted from an entity basis to a record (or person)
basis.  The record axis codes are assigned in terms of the set of codes that
best describe the overall medical certification portion of the death
certificate.'

The format of these conditions is a bit different then typical WLS variables.
The first position represents the line of the certificate on which the code
appears. The second position is the sequence indicator on the line. Positions
3-6 are the ICD-9/ICD-10 code. The 7th and last position is a nature of 
injury flag. One representing nature of injury codes and a zero 
representing all other cause codes. The seventh position is blank for ICD-10.

Also please note, ICD-9 variables from the phone interview and mail 
questionairre are collapsed into integers. Whereas, NDI goes to the tenths 
place with an implied decimal.


NOTE: Please see cor743b for the ICD-9 282 recodes, cor743c for the ICD-9 
      72 recodes, cor939b for the ICD-10 recodes. All are located in 
      Appendix R.
      

BRIEF VARIABLE DESCRIPTIONS

    NDI01:          State Graduate died
    
    NDI02-NDI04:    Graduate's cause of death codes
    
    NDI05-NDI25:    Graduate's entity-axis conditions
    
    NDI26-NDI46:    Graduate's record-axis conditions
    
    XNDI01:         State Selected Sibling died
    
    XNDI02-XNDI04:  Sibling's cause of death codes
    
    XNDI05-XNDI25:  Sibling's entity-axis conditions
    
    XNDI26-XNDI46:  Sibling's record-axis conditions

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