Event characterization in ALICE

This paper reviews the methods that will be used in ALICE, the dedicated heavy-ion experiment at the LHC, for the measurement of observables that characterize the global properties of the events. The basic capabilities of the experiment for the determination of centrality and the measurement of charged-hadron multiplicity in nucleus-nucleus, proton-nucleus and proton-proton collisions are shown. Finally, the results of a study of ALICE performances in the determination of the centrality dependence of the hadron multiplicity in PbPb events are presented.