The results obtained by the separate tests chosen should also be compared, for two tests may measure practically the same mental trait and have a very high coördination with each other. In such a case, it would seem almost a useless waste to retain in the group two tests which measured the same phase of ability. The one of the pair which showed the less close relationship to the true ranking might be dropped from the list without much loss to the total effectiveness of the group of tests. A group of tests thus carefully selected would prove very helpful and effective in the selection of untrained material for training or in the classification of experienced employees according to their intellectual qualifications for the type of position held by the people on whom the validity of the tests had been proved. The advantage of such a well-selected “team” of tests is not so much that it selects various grades of ability more accurately than supervisors could select it after many months of experience in trying to train the new material, but that the tests make a satisfactory classification immediately, which saves the salaries and time of those applicants who would certainly fail in the training period. Even with the very best coefficients of coördination between the tests and actual demonstrated ability in the trade or position, the tests will not be infallible. On the other hand, no supervisor’s judgment would be infallible, either. And the supervisor would be much more likely to make errors through personal likes and dislikes than the impersonal tests could possibly be. The tests are an invaluable aid, when they are themselves chosen with the scientific care outlined above, although it would be a short-sighted policy for any firm to trust entirely to the results of intelligence tests in the employment of its personnel. Appearance, voice, education, manners, physical size, and many other qualities are sometimes quite as important as the degree of intelligence, and the intelligence tests do not measure other elements of personality than the mental qualities. Warning should also be given against using a particular set of intelligence tests, selected because they show high correspondence with ability in salesmanship, for example, as a measure of the intellectual qualities of candidates for some other position. Sets of tests, selected because they have been found accurate in classifying soldiers or school children for instruction, may not be of maximum usefulness in classifying machinists or business managers. The Mentimeter tests offer a wide variety, from which it is proposed that only those shall be used which have actually proved useful in classifying candidates for the particular task concerned. There is no reason to believe that exactly the same type of intelligence is required in all positions.