Now, that is precisely what the employer of workers, the commander of soldiers, the teacher of a class or any one else charged with responsibility for the performance of any sort of tasks by any group of human beings, wants to know about the individuals under his direction. He should know or be able to determine readily not alone what each of the individuals can actually do and which ones can do particular tasks better than the others, but it is important for him to know the relative _capacities_ of the entire group, so that he can determine, as in the case of the automobiles which have been used as an illustration, which of them are most worth spending time and effort upon in the expectation that they will learn to do even more difficult tasks, and which of them are so hopelessly incapable that nothing is to be expected of them except the simplest routine performances. Now, the man who operates a fleet of automobile trucks does not stop when he has made a comparison of the vehicles in his garage with one another, but is constantly comparing the performance of each with standards established by other cars, machines of different makes, and with new machines. There exists, and he is constantly conscious of its existence, an ideal standard of performance for automobiles to which his cars must conform as nearly as possible if their service is to be satisfactory. So, in measuring human capacity, it is not enough to compare the individuals of a group with one another, though this is essential and for some purposes temporarily sufficient; there are available standards based upon the actual achievements of individuals of known capacity by which the mental powers of any and all individuals may be gauged. It will readily be seen that the employer of a number of persons—engaged, let us say, in some specific mechanical or clerical operation—needs to know not only whether some of these are capable of being trained to do better work and some so incapable of further training that it would be cheaper to discharge them and fill their places with more intelligent persons, but also to know how any particular group of employees compares in average intelligence and how each one of the group compares in individual intelligence with the average or higher-than-average capacity of those outside of his own particular business establishment who are engaged in similar work. This is a matter of dollars and cents to the employer. If he can obtain a standard that is universal or nearly so, that tells him, in fact, what all of the employers in his line of business have found to be the average or the limits of mental capacity possessed by workers of a particular class, then he is in a position to determine whether he is getting equally good service for the wages which he pays as is obtained by other employers requiring similar service.