This panel session paper outlines efforts to develop transient stability and voltage stability applications using phasor measurement units (PMUs). These efforts conducted in collaboration with three different utilities examine the use of decision trees (DTs) to identify critical attributes that need to be measured using PMUs to characterize important phenomena associated with system dynamic performance. A series of off-line analyses are conducted to appropriately train the decision trees and these decision trees are then updated in real time to account for changes in operating conditions and network topology. An important advantage of the DTs is that they provide a threshold for the limiting values of the selected critical attributes and also characterize a nomogram in terms of multiple critical attributes in the operating space. These applications are described for a range of stability phenomena.