[R] baseline cumulative hazard by basehaz()

[array chip]

Hi, 


basehaz() in survival package is said to estimate the baseline cumulative hazard from coxph(), but it actually calculate cumulative hazard by -log(survfit(coxph.object)). But survfit() calculate survival based on MEAN covariate value, not covariate value of 0. I thought baseline cumulative hazard means when covariate value is at 0. Did I misunderstand something?

Thanks

John