EMPLOYMENT PSYCHOLOGY I92 that records of this kind are frequently available, es pecially in the case of piece-workers. Such records, in spite of the varying conditions of production and manage ment which may tend to destroy their impartiality, are far more reliable and uniform than any other record which can be obtained. The personal opinions of foremen, in structors, or other superiors are at all times a poor sub stitute for such an objective-production record. However, the higher we go in the scale of work the less likely are we to find workers doing the same kind of work under con ditions which make it possible to measure and compare their relative output or production. Imagine trying to estimate and compare the work of the manager of one department with that of another. Manifestly, it is im possible to make such a comparison except in the most general terms, and in terms of personal opinions rather than in terms of an impersonal measure of units of work actually produced. These three conditions, therefore—first, the necessity for dealing with work which the psychologist can under stand, secondly, the necessity of trying preliminary tests on a large group engaged in the same kind of work, and thirdly, the necessity of an objective or impersonal measure of the work—set a distinct limit to the scope of psychologi cal tests, particularly with regard to the selection of big men. Psychologists, in their eagerness to live up to all the demands which have been put upon them, have some times hesitated to admit this limitation. They have allowed themselves to be credited, by the too interested friends of psychology, with a technique which enables them to select men for higher types of work. No one, more quickly than the employment manager, will recog nize the inadequacy of this technique when it is given