[R] Strang line while plotting failure curves
Frank E Harrell Jr
f.harrell at vanderbilt.edu
Thu Nov 6 22:24:30 CET 2008
Lu, Jiang wrote:
> Thank you very much, Frank. I installed Design package and tried
> #R code
> # End of R code
> I have achieved my goal with the 'fun' argument you advised. But I have
> a difficult time to do the following fine tune.
> 1. The X axis scale was labeled as 'Days'. I would like something like
> 'xscale=365.25' in plot.survfit to put time into Years and label the
> ticks from 0 to 5, instead of from 0 to 1826.25 by each 365.25
> increment. I tried xaxt='n' as you can see in the code above. Then I
> noticed that xaxt='n' only work for plot(survfit), not in survplot().
> Any advice how to change the tick label using survplot()?
There are options to do all that, described in the documentation.
> 2. The n.risk was beautifully printed for each specified time point
> along the x axis. However, since I am plotting the failure rate, the
> n.risk looks busy with the failure rate curves. Is there a way to move
> the n.risk to the top of the plot where there are lots of space?
May be best to move it to the bottom margin. See the help file.
> 3. I also tried label.curves=list(). It is very convenient. The curves
> are labeled and the legend is created as well. Could I only keep the
> curve label and get rid of the legend since the legend is not so
> necessary once the curve is labeled. How do you think?
Should be options for that too.
> I really appreciate any help you give.
> Best regards,
> Jiang Lu
> Department of Epidemiology
> University of Pittsburgh
> On Thu, Nov 6, 2008 at 1:21 PM, Frank E Harrell Jr
> <f.harrell at vanderbilt.edu <mailto:f.harrell at vanderbilt.edu>> wrote:
> Lu, Jiang wrote:
> Dear R helper,
> I encountered a problem when I tried to plot the cumulative
> failure rate
> (i.e. 1 - survival probability). I have used the following code
> to plot. The
> scenario is that patients are randomized to different treatment
> arm (rev in
> the code), the PCI revascularization was monitored over 5 years.
> #R code
> testfit <- survfit(Surv(pcifu,pci)~rev,data=subproc)
> testfit$surv <- 1 - testfit$surv
> testfail <- plot(testfit, mark.time=FALSE,col=1:2,
> main='Failure Rate')
> #End of R code
> I arbitarily replaced testfit$surv by computing 1 minus the original
> survival rate. So far so good. However, when I plot the manipulated
> "testfit", there is a vertical line plotted at x=0, y=0:1. I checked
> testfit$time and testfit$surv, nothing weird there. I am very
> confused where
> the vertical line at starting point of time 0 came from. How can
> I get rid
> of it?
> Would you pleae help me with this? Thanks a lot!
> Also see the survplot.* functions in the Design package and their
> fun argument, e.g., fun=function(y)1-y
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> Frank E Harrell Jr Professor and Chair School of Medicine
> Department of Biostatistics Vanderbilt University
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University
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