Dear Chiara,
your question might find some helpful answers in Cleves MA, Gould WW,
Gutierrez RG. An introduction to survival analysis using Stata. College
Station, TX: StataCorp, 2004: 65-66.
Id variable is particularly useful whenever you are dealing with multiple
records per subject in your dataset.
Should your dataset be a single-observation one(I mean, your data set
reports the median of unemployment duration measured in months for _n
individuals, assuming they are not hired-fired workers; let's say that your
data set includes 10 individuals only), you can generate id in the following
way (please, see short example below):
*************begin example****************
set obs 10
obs was 0, now 10
g id=_n
************end example******************
Sorry I cannot be more helpful.
Kind Regards,
Carlo
-----Messaggio originale-----
Da: [email protected]
[mailto:[email protected]] Per conto di Mussida Chiara
Inviato: venerd� 22 febbraio 2008 10.59
A: [email protected]
Oggetto: st: command: stpiece
Hi guys,
I'm trying to sort out a specification issue for stpiece analysis.
More precisely I must estimate a piecewise constant hazard model for U
duration (survival analysis). This, as you know, means to specify piece in
which the dependent variable (for my model it is the unemployment duration,
measured in months) is constant. The problem arise since, as stata help
suggests:
The data must be st. In order to create time pieces, an id variable
must be declared with stset. See st and stset.
Now: is the id variable an additional variable to ne generated, or it simply
refers to my dependent variable and therefore to the precise turning point
that I want to specify?? this point for me is the median of the dependent
variable distrn, and in a successive estimations there will be more time
intervals dictated by the relative frequency of the observations...
Thanks for your attention,
chiara
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