Distinguishing new physics scenarios with polarized electron and positron beams

Contactlike nonstandard interactions can be revealed only through deviations of observables from the standard model predictions. We consider a number of such nonstandard scenarios, and discuss their identification as sources of deviations in fermion-pair production processes at the International Linear Collider, if they were observed. We emphasize the role of e^- and e^+ polarization in enhancing the identification reaches.