Alternative Plans. The word "alternative" is generally applied to contingent plans intended to accomplish a common task, but developed from varying sets of assumptions. "A choice between several" is the meaning of the word as here used. When such choice becomes necessary in a situation not yet clarified, that plan will be selected which has been derived from the set of assumptions considered by the commander as most likely to be correct. The selected plan is usually called the plan or the "accepted plan", and the other plans, coming from other less likely but still possible sets of assumptions, are called Alternative Plan No. 1, Alternative Plan No. 2, etc. Naval tactical situations particularly lend themselves to the drawing up of alternative plans in advance. There are numerous general categories of such tactical plans. Among these the Battle Plan is of paramount concern. Others include plans for sortie, entrance, defense while cruising, etc. In each category, alternative plans may be developed, based on various sets of assumptions. Alternative plans evolved in advance of detailed information may be found useful as a general basis for action. Circumstances may prove to be different from those previously visualized. The correct procedure is to keep the plans up to date, testing them, by the latest information, in a Running Estimate (Chapter IX). The commander will thus have a foundation for sound decision in the circumstances which actually arise. Still another use of alternative plans merits consideration. Early coordinated action during actual operations may be demanded although neither time nor the information available has permitted a detailed estimate. If the commander has drawn up, in advance, plans based on assumptions as to conditions that conceivably might exist, he will be better able to appreciate the situations which actually arise. He can thus direct the necessary action with more rapidity and understanding than if completely unprepared because of lack of planning. If he informs his subordinates of his proposed action under certain assumed conditions, he will facilitate cooperation, because better mutual understanding will exist. The advance alternative plans here discussed are not necessarily confined to problems confronting a commander during actual war operations. They may profitably be drawn up in peace, and may be the basis of training exercises. Application of the Essential Elements of a Favorable Military Operation