help for starjas
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Title

starjas -- Arjas plot to check proportional hazards assumption

Syntax

starjas varname [if exp] [in range] [, adjust(varlist) levelplot(# [#] ..) atobs(#) rrglance(#) twoway_options ]

options Description ------------------------------------------------------------------------- Options adjust specify the variables fitted in the Cox model before checking if varname is proportional levelplot specify the levels of varname to be displayed in the plot atobs restrict the plot to the first # events rrglance draw a line approximately corresponding in the case of binary covariate to a # relative risk

Y-Axis, X-Axis, Caption, Legend twoway_options some of the options documented in [G] twoway_options Add plot plot(plot) add other plots to generated graph -------------------------------------------------------------------------

You must stset your data before using starjas; see stset.

Description

starjas graphs Arjas plot by one categorical variable declared in varname.

Arjas plots allow to check if a covariate should be included in a proportional hazards model and if it has proportional hazards effect. If a covariate does not need to be in the model, then for each level a roughly 45 line through origin should be plotted. Otherwise Arjas plot will give curves which are approximately linear but with slope differing from 1. If a covariate has a nonproportional effect on the hazard rate, then the curves will differ nonlinearly from 45 line. Assume an indicator variable having only two values, the curve for the level 1 should be concave if the hazard ratio is increasing in t whereas the curve for the level 0 should be convex.

Examples

use "C:\Data\BMT", clear starjas MTX, legend(pos(5) ring(0)) lw(medthick) starjas Z7cat, adjust(MTX Z1-Z6) legend(pos(5) ring(0)) lc(green navy red brown)

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

(click to run)

Also see

Manual: [S] st stcox

Online: stcox postestimation, stcox diagnostics

References

Klein JP, and Moeschberger ML: Survival Analysis: techniques for Censored and Truncated Data - 2nd ed. (2003), p. 369 - 374. Springer

Authors

Enzo Coviello (enzo.coviello@alice.it)