Complete renormalization group improvement - avoiding factorization and renormalization scale dependence in QCD predictions

For moments of leptoproduction structure functions we show that all dependence on the renormalization and factorization scales disappears provided that all the ultraviolet logarithms involving the physical energy scale Q are completely resummed. The approach is closely related to Grunberg's method of effective charges. A direct and simple method for extracting Lambda(<(MS)over bar>) from experimental data is advocated. (C) 2000 Elsevier Science B.V. All rights reserved.