---begin included message ---- Hi, i need to use pspline. In this pspline function coxph.wtest was used. When I try to make some change to this function by pulling out the pspline function, it turns out R gave me an error msg, saying coxph.wtest cannot be found. Even if i dont change anything in pspline and just rename it and run the function, it did not work out. Can any one help me with this? is there anyway to get the coxph.wtest function? thank you --- end included message Your question is not completely clear to me, but I will guess that you have "pulled out" some code from coxph and tried to run it separately. If so, you are running into the name space problem: not all functions within the survival package are visible outside of the package. (Those for which the authors assumed that "no one would call the function themselves".) A quick solution is to make your own local copy > coxph.wtest <- survival:::coxph.wtest It will now be visible to you. Terry T.