I have seen literature on using a combination of the 'strucchange' and 'segmented' packages to find and fit piecewise linear models. I have been trying to apply the same methods to quantile regression from the quantreg package, but am having issues using a "rq" object where the function assumes a "lm". Has anyone had this issue? -------------------------------------- Jonathan P. Daily Technician - USGS Leetown Science Center 11649 Leetown Road Kearneysville WV, 25430 (304) 724-4480 "Is the room still a room when its empty? Does the room, the thing itself have purpose? Or do we, what's the word... imbue it." - Jubal Early, Firefly [[alternative HTML version deleted]]