2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47863The size of non-perturbative corrections to event shape observables is predicted to fall like powers of the inverse centre of mass energy. These power corrections are investigated for different observables from $e^+e^-$-annihilation measured at LEP as well as previous experiments. The obtained corrections are compared to other approaches and theoretical predictions. Measurements of $α_s$ using power corrections are compared to conventional methods.6 pages, uses moriond.sty (included). Contribution to "Rencontres de Moriond, QCD and hadronic interactions", Les Arcs, France, March 1998High Energy Physics - Phenomenologytext