Re: scm problem

hi Muhammad, a brief guidance on how to do a stepwise covariate search with PsN+Pirana is given in our recent tutorial in CPT-PSP ( http://onlinelibrary.wiley.com/doi/10.1038/psp.2013.24/abstract), in which we used the scm tool in PsN, and Pirana to generate the scm config file. Let me know if you don't get the example to run. (Someone reported recently that the appendix files were not available anymore, but they are also here: https://github.com/ronkeizer/ppx_tutorial) Of course—if you keep having trouble getting the scm tool to run—you could choose to implement and run the covariate models manually: for only five covariates there is only little gain in using the scm tool. A gentle introduction on how to build covariate models in NONMEM is available in chapter 5.7 of the recent book by Owen and Fiedler-Kelly ( http://www.amazon.com/Introduction-Population-Pharmacokinetic-Pharmacodynamic-Nonlinear/dp/0470582294/ ). best regards, Ron PS. any Pirana-specific questions can also be posted at http://qa.piranasoftware.com