  Many particle physics analyses which need to discriminate some background
process from a signal ignore event-by-event resolutions of kinematic variables.
Adding this information, as is done for missing momentum significance, can only
improve the power of existing techniques. We therefore propose the use of
significance variables which combine kinematic information with event-by-event
resolutions. We begin by giving some explicit examples of constructing optimal
significance variables. Then, we consider three applications: new heavy gauge
bosons, Higgs to $\tau\tau$, and direct stop squark pair production. We find
that significance variables can provide additional discriminating power over
the original kinematic variables: $\sim$ 20% improvement over $m_T$ in the case
of $H\rightarrow\tau\tau$ case, and $\sim$ 30% impovement over $m_{T2}$ in the
case of the direct stop search.
