It is for motion study to explain the methods of deducing standard methods by using activity records obtained through the various types of motion study data. Many such standards have been derived. We have in our motion study data many elementary motions with records of the space they cover and the amount of time they require. With these we can test the given work to see which of these motions it includes. Having tabulated this, we can make an intensive study of the motions that remain. When this study has been made, we can combine the resulting elementary motions that have proven themselves most efficient into the working method, and classify the work as work of a type requiring a certain set combination of motions. Testing Workers by Motion Capabilities. In the same way we may test a worker by motion learning capabilities, before assigning him to any kind of work. Having reduced activities to their motions, we can test the worker’s physical capability; his mental capability we can test by determining his learning curve. To these results we add a record of his interest in various types of work. From the resulting three types of records, we can make placements that, we believe, are far in advance of any that have been made up to the present time. The Use of Activity Records as Data for Eliminating Fatigue. The fact that activity records are made of extremely small elements moving through a short path in a small amount of time means that the fatigue records cover the same short periods. This is a great help in making fatigue study. A new combination of elements of activity will also mean a combination of concurrent, or included, elements of fatigue. The combination may have some effect on the activity. If so, it will also affect the fatigue, but at the present state of the art the most accurate and satisfying work can be done by making use of activity records to eliminate unnecessary fatigue, without waiting for some hypothetical, direct records of fatigue, that may be worked out in the future. In other words, if you have accurate records of fatigue included in your activity records, use these immediately, without attempting to make separate records of the fatigue, that, while valuable, will mean delaying fatigue elimination, perhaps indefinitely. The Time Element.