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Xpose 4.0 release 1 now available! 2008-06-13 09:54 - Xpose
Our first non-preview release! This version of Xpose incorporates visual and numerical predictive check capabilities, in concert with Perl-speaks-NONMEM (http://psn.sf.net). For more information type, at the R command line:
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Update 1 to release 6 2007-05-31 20:27 - Xpose
A quick bug fix for titles of plots with multiple graphs. Now they can be specified to be anything the user desires. Just use the 'main' argument at the command line.
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Xpose 4 preview release 6 now available 2007-05-30 12:03 - Xpose
A new release of xpose is now available. This release changes the default way tables should be created so that xpose can calculate the CWRES, see the help page for 'compute.cwres' for more information. This release also updates the 'mirror' option, all plots in xpose can now handle the mirror option to create simulated comparison plots.
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Xpose 4 release 5 update 1 now available 2007-03-20 08:02 - Xpose
Xpose 4 release 5 update 1 is now available. This release fixes some small bugs and updates the methods used in the mirror functionality of the plots available in Xpose.
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Preview Release 5 Available 2007-02-27 14:11 - Xpose
Xpose 4 preview release 5 is now available! This release fixes a bug found in the CWRES calculation, that affected results if the ID's in a NONMEM dataset were not in order (i.e. if ID=2 was before ID=1). The CWRES will still have a problem if two separate individuals have the same ID value in a NONMEM dataset (but this, we believe, is a rare occurance). A new plot of the CWRES and WRES vs. PRED is also included in this release.
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Overview of Xpose

Xpose is an R-based model building aid for population analysis using NONMEM. It facilitates data set checkout, exploration and visualization, model diagnostics, candidate covariate identification and model comparison.

Data set checkout includes visualization of the observed variable(s), covariates and plots to reveal errors in the data file.

Model diagnostic plots includes the usual residual plots but also plots to check the validity of assumptions specific to non-linear mixed effects models.

Data exploration is also done by various plots but also includes auxiliary screening analyses such as stepwise generalized additive modeling (GAM) and tree based modeling.

The stability of the GAM results with respect to covariate model selection as well as the impact of influential individuals and certain types of covariate interactions can be explored using a bootstrap re-sampling procedure.

To facilitate documentation, Xpose can produce run summaries and run records. The run records are one page summaries of a run consisting of a combination of goodness of fit plots, parameter estimates and the model file. Run records are tabulated summaries of many runs consisting of user comments, termination messages and objective function values.

The Xpose development team consists of Andrew Hooker, Justin J. Wilkins, Mats O. Karlsson and E. Niclas Jonsson. We are based at the Division of Pharmacokinetics and Drug Therapy, within the Department of Pharmaceutical Biosciences at Uppsala University.