Re: st: Changing range in sts graph

[Mark Lunt <Mark.Lunt@manchester.ac.uk>]

Svend Juul wrote:
> Diego Bellavia <messadua@yahoo.it> wrote:
>
>   
> > I have a Kaplan Meyer curve I built with sts command. 
> > The curve is nice but I would like to reduce the range of time showed
> > to highlight the first part of the graph (where I have more events).
> > I tried with the xscale (range (0 100)) option but without success. 
> >     
> Maarten suggested:
>
>    sysuse cancer, clear
>    stset studytim,failure(died)
>    sts graph 
>    sts graph if _t < 20
>
> and Allen Buxton suggested:
>
>    local rangelimit=100
>    replace _d=0  if _t>`rangelimit'
>    replace _t=`rangelimit' if _t>`rangelimit'
>
> Nick got nervous:
>
> Doesn't any messing with _t mess up anything later with the same 
> survival dataset? Sounds a bad idea to me. See Maarten's solution. 
> -----------------------------------------------------
>
> Allen's suggestion is right, Maarten's is wrong. It is easy to
> see with -sts list- :
>
>    sysuse cancer, clear
>    stset studytim,failure(died)
>    sts list 
>    // Maarten's suggestion:
>    sts list if  _t < 20    
>    // Allen's suggestion (simplified):
>    replace _d=0  if _t>20
>    replace _t=min(_t,20)
>    sts list
>
> In Maartens suggestion, persons surviving 20 months or more
> were excluded from the analysis, leading to a far too pessimistic
> survival estimate at 19 months. In Allen's suggestion they
> are correctly censored at 20 months.
>
> Svend
>
>   
There is the option tmax, which truncates the display of the curve at a 
given time, without needing to play with the data: should keep everyone 
happy.

Mark

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