The production, annihilation, and accumulation of point defects in metals during displacive irradiation is dependent on a variety of physical conditions, including the nature and energy of the projectile particles and the irradiation temperature. This paper briefly reviews the evolution of the defect population in an isolated displacement cascade, and outlines a proposed framework for identifying the relevant components of displacement damage and defect production under cascade damage conditions. The most significant aspect of energetic cascades is that the concepts of atomic displacements and residual defect production must be treated separately. An evaluation of experimental and computer defect production studies indicates that the overall fraction of defects surviving correlated annihilation in an energetic displacement cascade in copper decreases from about 30% of the Norgett-Robinson-Torrens (NRT) calculated displacements at 4 K to about 10% of the NRT displacements at 300 K. Due to differences in the thermal stability of vacancy versus interstitial clusters, the fractions of freely migrating defects available for inducing microstructural changes at elevated temperatures may be higher for vacancies than for interstitials. The available evidence suggests that the fraction of freely migrating vacancies at temperatures relevant for void swelling in copper is greater than or similar to 5% of the calculated NRT displacements.