(a) It is based on actual figures, easily extracted from the regular books of account, and which are a true statement of fact; no guess─work or estimating about it. There is no better way to figure what is to be, than to use results of what can be conclusively demonstrated already has been. (b) It can be used in any manufacturing plant, or in all the departments of the same plant, thereby insuring uniformity of method, which is always desired. No argument is necessary to convince that two methods in the same factory are undesirable when one can be found that is satisfactory. (c) It accomplishes its purpose──it distributes. If it is found that factory conditions are changing, the percentages used may also be changed so as to increase the amount of expense distributed, or diminish it, as necessary. (d) It requires less work for the cost accountant. The man─hour plan requires the hours worked to be recorded and footed in addition to the labor cost. The machine─rate plan requires not only two different calculations, as already shown, but also necessitates the adding of all the hours worked. The percentage plan requires only the labor cost in money value, and renders the recording and adding of long columns of hours entirely unnecessary, which, as can readily be seen, is an immense saving of labor. In a large plant with an elaborate system of job orders to be handled, the value of the percentage method, in doing away with this double calculation, will be appreciated immediately. [Illustration: BROOKLYN, N. Y., PLANT OF THE H. W. JOHNS─MANVILLE CO.] (e) Figuring by percentages can be done rapidly, and in many instances it is but a mental calculation and almost instantaneous. Were hours recorded, the frequent use of fractions would render the process of figuring expense less rapid. (f) It is an equitable means of distribution, for it is based on the direct labor cost, which is not only the most reliable element of cost to use as a basis, but which is one of the principal factors by which the amount of expense is influenced. (g) It has the endorsement of our best factory accountants and auditors, and it is noted that where "systems" are being installed by factory organizers to─day, the percentage method is continually being adopted as the most satisfactory, for it brings the best results with the least machinery to operate. PERCENTAGE METHOD EXEMPLIFIED =11.= Before proceeding to show in detail the method to be pursued in arriving at the various percentages to be used in distributing expense by the _percentage method_, it may be well at the outset to clearly understand what constitutes _productive labor_ and _expense_, or _non─productive labor_, for it is on the former that all calculations are based.