[EpiData-list] France

epidata-list at lists.umanitoba.ca epidata-list at lists.umanitoba.ca
Sat Dec 20 10:58:35 CST 2008


I think that the problem is a bug in the estimation of median survival 
proportions when there are no survivors in one group (for plaisir=3, all 
8 records have arret=1).
If you invert plaisir, by the way, (recode 1 to 2, 3 to 1), it may work, 
but not consistently.
If you want the p50, then you can run the analysis for level 3 of 
plaisir alone:

lifetable arret durall /p50 if plaisir=3

This seems to work all the time.


Bernard wrote:
> For your interest, I join a file with four variables and 239 lines.
> "Arret" is outcome variable (1=interest), and "durall" time variable in
> weeks. Plus two variables "plaisir" and "moment" in two categories (1 and
> 2).
> The result of lifetable command with "lifetable arret durall /by=plaisir
> /p50 /t" is curious (with version 159 and anterior) instead of "7" or "8"
> for the categorie "plaisir=2" (probability of 0.50). It's OK with variable
> "moment"

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