JOB ANALYSIS 259 method. This method has already been described. To begin with, it makes a thoroughgoing analysis of one job and then, on the basis of this study, selects a set of tests which seem to involve the same ability as that required by the job. These tests are then tried out on a large number of workers whose ability is known in order to find those tests which do this to the highest degree. When tests which are sufficiently significant are found, the result is a standard and scientifically accurate measurement of those specific abilities which are required by that specific job. It is unnecessary to name these abilities even. The qualities required by a successful inspector, for instance, need not be called good visual discrimination, quick- reaction time, and steady attention. These names are also general and serve merely as a starting point. The requirements of this job may be stated simply as the ability to reach such and such a standard in tests number two, six and eight. There is nothing vague, abstract, or general about an analysis of this kind, any more than there is about the chemical formula HnOy or the formula in . . weight in lbs. • , , , physics, mass ——2 lhe job has been an- 32.16 alyzed in a scientific manner, in such a way that the abilities required by that job can be definitely and mathe matically gauged. A job analysis of this kind is a long and careful proc ess, and can be made only by persons equipped with the proper technique. In the meanwhile, a temporary job analysis must be made to meet the immediate needs of the employment office. In making such an analysis, the application of psychological principles will be of utmost value. Let us suppose that a representative manufacturing