“Upon the information of the enemy and of the terrain obtained by reconnaissance, and, as far as time will permit, upon the study of the terrain made by the leader in the field of probable operations, the plan of action is based.” So state our Field Service Regulations.[4] Decision, then, is built upon the amount of material that the observation and attention of a commander can collect. And it is only his observation and attention which count. It is only what he himself has fixed in his own mind which is going to do the troops harm or good. He may receive dozens of excellent messages, or may view the battle-field for twenty miles; yet it is only what he himself appropriates to his own straight thinking, which can influence the outcome. The reports or the visions of others cannot enter into the decision, unless he has transferred those reports or visions to his own calculations. How can he weigh what he has not handled—consider what he has not absorbed? The decision of a leader issues from the door of his own observation and attention. The most pertinent facts may be laid at that threshold only to be shut out because he has not increased his capacity to take them in. And no one else can enter there in order to do the work for him unless the intruder becomes virtually, if not actually, the leader.
THE ESTIMATE
Let us suppose that the observation and attention have taken in all that they should. These various items lying in a more or less jumbled mass must now be sorted. Information of one class must not be found mixed with that of another class. Each organized body of information must approach the leader’s judgment by itself so that: (1) nothing will be overlooked; so that (2) each item will be with its proper set. After they have all passed through his thought, certain ones, of course, may be discarded; but they all must none the less be first reviewed consciously by the leader. This process is called the estimate of the situation. In order, therefore, to comply with the full conditions of such an estimate, a fixed classification of all the essentials which should go through the hopper of a leader’s judgment has been made. After his information has been obtained and before his decision has been formed, the leader must say to himself:—
1. What is my mission?
2. What are the forces—the enemy’s and my own?
3. What conditions are favorable and what unfavorable?
4. What is the enemy doing and what will he probably do?
5. What effect has the terrain upon my mission?
6. What different courses are open to me in order to carry out my mission, and what are the advantages and disadvantages of each?