The author of this passage is in grave danger of disappearing up his or her rear end. I can't see where "-werte" adds anything, except that he or she had got three quarters of the way through the sentence without talking about "Werte", and was doubtless fearful of reaching the end without having used the "concept".

If you want to put "on the basis of the values acquired from many years of experience" or something equally nonsensical, I don't blame you. I am reminded of the old computing saying "garbage in, garbage out".

another option