Hello I would like to compare the results obtained with a classical non parametric proportionnal hazard model with a parametric proportionnal hazard model using a Weibull. How can we obtain the equivalence of the parameters using coxph(non parametric model) and survreg(parametric model) ? Thanks Virginie
On Thu, Jan 20, 2005 at 03:18:53PM +0100, Virginie Rondeau wrote:> Hello > I would like to compare the results obtained with a classical non > parametric proportionnal hazard model with a parametric proportionnal > hazard model using a Weibull. > > How can we obtain the equivalence of the parameters using coxph(non > parametric model) and survreg(parametric model) ?One way of avoiding this problem is to fit the Weibull model with 'weibreg' in the package eha. -- G?ran Brostr?m tel: +46 90 786 5223 Department of Statistics fax: +46 90 786 6614 Ume? University http://www.stat.umu.se/egna/gb/ SE-90187 Ume?, Sweden e-mail: gb at stat.umu.se
Virginie Rondeau wrote:> Hello > I would like to compare the results obtained with a classical non > parametric proportionnal hazard model with a parametric proportionnal > hazard model using a Weibull. > > How can we obtain the equivalence of the parameters using coxph(non > parametric model) and survreg(parametric model) ? > > Thanks > VirginieIn the Design package look at the pphsm function that converts a survreg Weibull fit (fitted by the psm function which is an adaptation of survreg) to PH form. -- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University