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RE: st: Multilevel modelling of survival data

From   Maarten buis <>
To   stata list <>
Subject   RE: st: Multilevel modelling of survival data
Date   Mon, 16 Mar 2009 21:17:43 +0000 (GMT)

--- On Mon, 16/3/09, Justin B Echouffo Tcheugui wrote:
> I tried the command stcox with the option -shared () as
> you advised. As you can see below I am not having the
> desired output:
> could not calculate numerical derivatives flat or
> discontinuous region encountered r (430)

One posibility that jumps to mind is: are there any
clinics that only have (valid) observations on either
the treatment or the controll group?

So type:

tab randomgroup clinic, if !missing(_t)

and see if any of the reported counts equal zero.

-- Maarten

Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen


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