As previously noted with respect to suitability, it may be desirable to consider, with regard to consequences, the detailed operations which may be involved in each course of action. Courses of action involving excessive consequences as to costs are rejected. Notation is made of the relative degree of acceptability, with respect to consequences as to costs, of those courses of action which are retained. (2) Details. (a) The Results of Success and of Failure. Each course of action is examined to visualize the situation which would be brought about for the commander and for the enemy in case of success or of failure. The relative possibilities of recovery toward a more favorable situation are weighed. This consideration involves relative risks, for it may be that a certain course, otherwise satisfactory, might entail intolerable conditions should failure ensue. The costs are measured in terms of fighting strength. It has to be considered whether the sacrifices involved are worth the gains which will follow; whether the objectives if attained will be sufficiently valuable when the need of fighting strength to accomplish further aims is considered. (b) Comparison of gains and costs. When costs are found to be in excess of the over-all gains, this fact may be the basis for rejecting any courses of action which are less desirable than others. However, retention of a course found to be costly may be justified for sound reasons. * * * * * When, as in the example given previously (page 96), the commander receives a directive such as "Deny enemy base sites in the area ABCD by capturing X Island", he carries through his estimate of the situation in the usual manner. He notes, however, that the capture of X Island has been indicated as a predetermined course of action. He makes a proper survey of the factors of relative fighting strength. He considers all pertinent courses of action. He goes through this procedure in order to reach an understanding of all the elements of his problem. He wishes to understand the necessary background. He realizes the importance of a grasp of the considerations which have led higher authority to arrive at the predetermined course of action. By carrying through the usual estimate procedure, including the analysis of all pertinent courses of action, he assists himself to arrive at a proper concept of the action to be taken to capture X island. In this way he establishes a sound basis for formulating a detailed plan (in the second step), for inaugurating planned action (in the third step), and for supervising this action (in the fourth step). He also establishes a basis for any constructive representations which he finds it advisable to make to higher authority (page 15).