Dear all, I would like to inform you about the new user-contributed package "PanelTools" which is a collection of functions for dealing with panel datasets. Most functions are extending the range of useful built-in functions such as psum() (http://gretl.sourceforge.net/gretl-help/funcref.html#psum) and pxsum() (http://gretl.sourceforge.net/gretl-help/funcref.html#pxsum). Have a look by simply running: <hansl> pkg install PanelTools include PanelTools.gfn help PanelTools </hansl> If you have further ideas, don't hesitate to request features or to send code. Best, Artur