  If a signal for physics beyond the Standard Model is observed at the Tevatron
collider or LHC, we will be eager to interpret it. Because only certain
observables can be studied at a hadron collider, it will be difficult or
impossible to measure masses and spins that could easily establish what physics
was being seen. Nevertheless, different underlying physics implies different
signatures. We examine the main signatures for supersymmetry, with some
emphasis on recognizing supersymmetry in parts of parameter space where generic
signatures are reduced or absent. We also consider how to distinguish
supersymmetry from alternatives that most closely resemble it, such as
Universal Extra Dimensions (UED). Using the robust connection between spins and
production cross section, we think it will not be difficult to distinguish UED
from supersymmetry. We expect that by considering patterns of signatures it is
very likely that it will not be difficult to find a compelling interpretation
of any signal of new physics.
