In order to evaluate the performance of shock mountings in a simple manner, it is very desirable to express by a single quantity the liability to damage of the contents of fragile equipment. The conditions on shock duration under which the acceleration, displacement, or velocity associated with the input transient may be employed to describe the liability to damage in place of the full shock spectrum are therefore discussed.In shock‐mounted equipment it often appears desirable to avoid mechanical elements that, by virtue of their low resonant frequencies, are sensitive to changes in displacement or velocity. If this is possible, acceleration remains as the factor of chief concern, and a mount must be chosen to provide an acceptable compromise between the resulting reduction in acceleration and the introduction of relative motion. Characteristic curves facilitating this choice are proposed, and the influence of mount nonlinearity and damping on the curves is briefly discussed.