α s 2002

An update of measurements of the strong coupling constant α s is given, representing the status of September 2002. The results convincingly prove the energy dependence of α s and are in excellent agreement with the expectations of Quantum Chromodynamics, QCD. Evolving all results to the rest energy of the Z 0 boson, the new world average of α s ( M Z ) is determined from measurements which are based on QCD calculations in complete NNLO perturbation theory, giving α s ( M Z ) = 0 . 1183 ± 0 . 0027 .