In measuring the results of air interdiction, the ideal source of damage information is a timely ground reconnaissance of target areas after strike. The effect of this damage is best seen by obtaining objective enemy assessments of the impact the damage had on enemy capabilities, plans, and operations. When this ideal method of measurement cannot be employed, as in the Korean War, the effectiveness of air interdiction must be weighted on less reliable scales. Damage information comes from after-strike photographic interpretation, aerial observer reports, claims by pilots of striking aircraft, intelligence agent reports, and prisoner of war interrogations. Best evaluations of the effect of the reported damage come from those who are able to judge intelligently enemy capabilities, enemy intentions, and the combat situation as it was before and after the interdictory effort. Statistical errors and some bias in judgement are inherent weaknesses of such assessments. These evaluations are nonetheless useful, the most useful undoubtedly being the consensus of all assessments made.