Hi All, I am trying to use the segmented package to determine the break point in a simple quadratic regression. I am receiving the error "(Some) estimated psi out of range" I searched the message board and found others that have had the same issue, but no clear solutions have been provided. Does anyone know of a solution to this error? Here is my model and segmented code. aclmfit<-lm(caliper~TreeAge + TreeAge2, data=ac2) ac.seg<-segmented.lm(aclmfit,seg.Z=~TreeAge + TreeAge2, psi=list(TreeAge=c(3,4,5), TreeAge2=c(0,16,25))) Thanks for the help, Alex -- Alexander R. Sherman ISA Certified Arborist NE-6472A Research Assistant Department of Environmental Conservation University of Massachusetts Room 225 160 Holdsworth Way Amherst, MA 01003