Dear Statalister,
A reviewer from a medical journal has asked me to provide 95% CI and
p-value for two nested Cox models of a Harrell C statistics
comparison.
Please help.
For instances,
Model1= stcox x y, efron
estat concordance=harrell1
Model2 stcox x y z, efron
estat concordance=harrell2
harrell2 - harrell1......xx, 95%CI(xx-yy); p=x.xx
or maybe harrel2/harrel1 (I am not sure which way)
Maybe boostraping the difference.
I would appreciate any help on this issue.
Eduardo
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