.-
help for ^stphplot^
.-

LogLog Plots For Assessing Proportional Hazards:                [STB-35 gr23]  
------------------------------------------------
(J.M.Garrett 12/12/96)

   ^stphplot^ [^if^ exp] [ ^,^ ^by(^classvar^) adj^ust^(^covlist^) str^ata^(^varname^)^
                       graph_options ^nosh^ow]


^stphplot^ plots -ln(-ln)survival vs. ln(time) by categories of a nominal X
    variable using Kaplan-Meier estimates; separate curve is plotted for each
    category of X; if adjust() is specified, covariates are automatically 
    centered; useful for graphically assessing the proportional hazards
    assumption -- the assumption is not violated when the curves are parallel.
    You must have ^stset^ your data before using this command; see help @stset@.


Options required
----------------

   ^by(^class_var^)^ -- separate curve for each category of class_var;
        produces separate survivor functions by making separate calculations
        for each group identified by equal values of the by() variables.

   ^strata(^class_var^)^ -- separate curve for each category of class_var;
        stratified estimates (equal coefficients across strata but baseline
        hazard unique to each stratum) are then estimated. May be used with
        adjust() in place of by()

 

Options allowed
---------------    

  ^adjust^ -- optional with by(); required with strata()
  ^noshow^ -- prevents ^stphplot^ from showing the key ^st^ variables
  graph_options -- most of the options available in ^graph^
   

Examples
--------

 . ^stset weeks relapse^
 . ^stphplot, by(trtment)^

     Plots the -ln(-ln) survival curves for weeks to relapse for leukemia
     patients by each category of treatment


 . ^stset days died^
 . ^stphplot, by(celltype) c(llll) xlabel ylabel^

     Plots the -ln(-ln) survival curves for days until death for lung cancer
     patients by each category of cancer cell type; connects points with lines
     and specifies axes

 . ^stphplot, strata(celltype) adj(age therapy)^

     Repeats previous example, stratified on celltype and adjusted for age and
     prior therapy

Also see
--------

    STB:   gr23 (STB-35)
 Manual:   ^[R] st sts graph^
           ^[R] st stcox^
 On-line:  help for @st@, @sts@