It is shown that it is possible to recast the usual canonical conditions for predicting stability-in-the-large for reactor-kinetics systems into terms of the parameters characteristic of the physical system, thus permitting direct qualitative examination of the stability of a given system. For systems with more than one reactivity coefficient, it is found as a direct consequence of the physical formulation that if the prompt coefficient is negative then a delayed positive coefficient can be more stabilizing than a delayed negative coefficient.