Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

st: RE: RE: Code to generate a difficult variable


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: RE: Code to generate a difficult variable
Date   Thu, 5 Feb 2009 10:35:19 -0000

This can be telescoped into 

bysort Study_id : gen failure = _n == _N & !missing(deathdate)

Nick 
n.j.cox@durham.ac.uk 

Howard Lempel


I can't test this because I don't currently have access to Stata, but
try the following:

sort Study_id
by Study_id: gen failure = 1 if _n==_N & !missing(deathdate)
replace failure = 0 if failure==.

Polis, Chelsea B. [cpolis@jhsph.edu]

I am setting up data for survival analysis on time-to-death.  I am using
time-varying covariates, so I have multiple records for each individual.
The column recording my date of death variable was imported such that
the
date repeats in every record, although it will be unnecessary
information
at all rounds except the last.  Different women contributed different
numbers
of rounds, ranging from 1 to 8.  I'd like to generate a new variable to
indicate failure, such that failure=1 only for the last record for each
individual woman, and only if she has a recorded date of death.

To provide a visual, I have study_id, numrounds, and deathdate,
available,
but would like to write code to be able to generate failure
automatically.
Is this possible?  I assume it would have something to do with _n, and
perhaps a foreach command, and an if statement, but I have no idea how
to
actually go about writing this, or figuring it out via help.  Any
suggestions?

Study_id        numrounds       deathdate       failure
1               1               03jul2005       0
1               2               03jul2005       0
1               3               03jul2005       0
1               4               03jul2005       1
2               1               .               0
2               2               .               0
2               3               .               0
3               1               15jun2004       1
4               1               .               0


*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index