Flexible parametric alternatives to the Cox model: update

Royston (2001)and Royston and Parmar (2002) introduced flexible parametric models for survival analysis, implemented in Stata through the ado-file stpm (Royston 2001). In the present article, stpm is updated to Stata 8.1 and has been shown to work correctly with Stata 8.2. To increase the reliability of the estimation procedure, the basis functions of the splines used to approximate the baseline distribution function have been orthogonalized. Copyright 2004 by StataCorp LP.