st: RE: zoom in on a Kaplan-Meier plot (display only a subset of the time axis)

["Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu>]

I tried this using _t and using t, and both gave me a zoomed in graph.
The first part of the graph was identically equal to 1.  uSING tmax and
tmin I got the subset you want.
I'll send it off line to you.
 

Tony

Peter A. Lachenbruch
Department of Public Health
Oregon State University
Corvallis, OR 97330
Phone: 541-737-3832
FAX: 541-737-4001


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Jacob Wegelin
Sent: Wednesday, October 01, 2008 1:51 PM
To: statalist@hsphsun2.harvard.edu
Subject: st: zoom in on a Kaplan-Meier plot (display only a subset of
the time axis)

Is there a way to create a Kaplan-Meier plot that is "zoomed in" on a
subset of the time axis? To make this concrete: It is easy to create a
twoway plot that is "zoomed in" on a portion of the axes, for instance:

clear
set seed 5
set obs 30
gen ID=_n
gen x=invnormal(uniform())
gen y= -2 * x + invnormal(uniform())
twoway (scatter y x , aspectratio(1))
twoway (scatter y x if x<1/2 & x>0, aspectratio(1))

/*
The second plot "zooms in" on the first.

But what if we have survival data? The second sts graph command below
does *not* do what I want; it creates a subset of the data and builds a
Kaplan-Meier plot afresh using that subset.  Is there any
straightforward way to make a "zoomed-in" Kaplan-Meier plot? 
/*

clear
set seed 5
set obs 30
gen ID=_n
gen t=exp(uniform()) - 1
stset t
sts graph 
sts graph if t > 0.5 & t < 0.8


Thanks for any ideas

Jacob A. Wegelin
jwegelin@vcu.edu 
Assistant Professor
Department of Biostatistics
Virginia Commonwealth University
730 East Broad Street Room 3006
P. O. Box 980032
Richmond VA 23298-0032
U.S.A. 
http://www.people.vcu.edu/~jwegelin


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