To determine the relative intelligence of five hundred men in fifty minutes by a method so completely objective that no part of the resulting classification is based on the individual judgment or opinion of either the examiner or any of the men themselves is certainly a practical application of psychological science. Simple as the Alpha test was, its practical working out and reduction to an exact scientific formula was the work of hundreds of highly trained minds for many months. In its concrete application it looks like a children’s game, but the results are so reliable as to be almost uncanny in the precision with which they tally with the conclusions reached in the same cases as a result of long and intimate observation. (For full details of the Alpha test the reader is referred to Appendix B to this volume.) The highest score a man could make in the Alpha test was 212. This is an absolutely perfect score, a correct answer or response to every one of the 212 questions or examples; but any man who made a score above 135 was given the highest possible rating, Grade A, in the mental schedule. There were seven ratings in all: A, above 135; B, which included those making 104 to 135; C, _plus_, which took in those down to a score of 75; C, for those scoring from 45 to 74; C, _minus_, for those with scores of 25 to 44; D, for the ones who gave from 15 to 24 correct answers; and D, _minus_, for those who were unable to answer correctly more than 14 out of the 212 questions. Now for the proof! Here is an official report of one of many comparisons made between the results of the psychological tests and the actual observations and personal knowledge of men by their officers. The commanding officers of ten different organizations, representing various arms of service in one camp, were asked to designate (a) the most efficient men in their organizations, (b) the men of average value and (c) the men so inferior that they were barely able to perform their duties. The officers had been with these men from six to twelve months and knew them exceptionally well. The total number of men rated was 965, about equally divided between the three classifications. After the officers’ ratings had been made, the men were given the Alpha test, and the comparison of results showed that the average score recorded in this test by those men the officers had graded as “best” was approximately twice as high as those the officers termed their poorest men. Of men scoring C, _minus_, in the Alpha test, 70 per cent. were those classed by the officers as their poorest men and only 4.4 per cent. of those ranked with the ones whom the officers regarded as best. Of all the men whose scores were above C, _plus_, 55.5 per cent. had been graded by their officers as their best men and only 15 per cent. as among their poorest soldiers.