help for stcband
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Title

    stcband --     Hall-Wellner and equal precision confidence band for the
                     survival and cumulative hazard function


Syntax

        stcband [if] [in] [, nair tlower(#) tupper(#) na transform(string)
               genlow(newvar) genhigh(newvar) level(#) nograph twoway_options
               ]


    options                        Description
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    Options
      nair                         specify equal precision (Nair) confidence
                                     band be computed. Default is
                                     Hall-Wellner confidence band
      tlower                       specify the lower time boundary for
                                     confidence band. Default is the smallest
                                     time event
      tupper                       specify the upper time boundary for
                                     confidence band. Default is the largest
                                     time event
      na                           compute confidence band for the cumulative
                                     hazard function
      transform                    produce log, linear or arcsine transformed
                                     confidence band. Default is log
      genlow                       create a variable saving lower confidence
                                     band
      genhigw                      create a variable saving upper confidence
                                     band
      level                        set confidence level. Values allowed are
                                     90, 95 and 99. Default is 95
      nograph                      suppress graph


    Y-Axis, X-Axis, Legend
      twoway_options               some of the options documented in
                                     [G] twoway_options

    Add plot
      plot(plot) addplot(plot)     add other plots to generated graph
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    You must stset your data before using stcband; see stset.


Description

stcband graphs and optionally saves the confidence bands for the survival
function.

The usual pointwise confidence intervals for the survival function are valid
for a single fixed time. Often limits which contain S(t) for all t in an
interval [tlow,tup] are of interest. Two important types of confidence bands
are the Hall-Wellner bands (Hall and Wellner, 1980) and the equal precision
bands (Nair,1984).  To construct these confidence bands critical values are
taken from NairTables.dta or HallWellnerTables.dta (see reference).  There are
three possible forms for the confidence bands: linear, log-minus-log and
arcsine-square root transformed.



Examples

            use "C:\Data\BMT", clear
            stset Time2,failure(DeathRelapse)


    Graph equal precision 95% confidence band in time interval 100 - 600 in
patients with acute lymphoblastic leukemia

            stcband if Dis==1, nair tlower(100) tupper(600) xla(0(100)600)
                    yla(0(.2)1, gstyle(minor))


    Generate and graph Hall-Wellner 95% confidence band in time interval 100 -
600

            stcband if Dis==1, tlower(100) tupper(600) genlo(lohw_band)
                    genhi(uphw_band) xla(0(100)600) yla(0(.2)1, gstyle(minor))


    Graph simultaneously pointwise log-log confidence interval and Hall-Wellner
arcsine transformed 95% confidence band

            sts gen pw_lo=lb(s) pw_hi= ub(s) if Dis==1
            stcband if Dis==1, tlower(100) tupper(600) xla(0(100)600)
                    transform(arcsine) yla(0(.2)1, gstyle(minor))
                    legend(ring(0) pos(7) size(*.7)) plot(line pw_hi pw_lo _t
                    if _t<600, sort c(J J) lc(red red))


Downloading ancillary files in one of your `"`c(adopath)'"' directory you can
run this example.

          (click to run)



Also see

    [ST] sts gen



References

Klein JP, and Moeschberger ML: Survival Analysis: techniques for Censored and
Truncated Data - 2nd ed., pp. 109 - 117.  New York: Springer-Verlag, 2003

Authors

Enzo Coviello (enzo.coviello@alice.it)