Page:Graphic methods for presenting facts (1914).djvu/215

 found feasible to keep on the chart pins relating to four different periods of six months each, so that every six months one color of pins would be removed from the board and the pins removed would be those which had been placed in the board two years previously. A board would then show at all times the record of cost in handling this particular commodity during the last two years. Boards used where pins must be put in and taken out very often may be faced with cork composition so that the pin holes may injure the surface as little as possible. Where pins are not to be changed very frequently, the straw-board covered with a layer of cloth before the co-ordinate paper is mounted will be found entirely satisfactory.

In the upper portion of Fig. 159 is shown a summary chart of the data contained on the pin board itself. Curve "C" is a smooth curve drawn through the center of gravity of all pins on any vertical line which shows the size of order. It will be noticed that the cost decreases very little when orders become larger than three hundred packages, but for this particular commodity with the methods of handling used, the cost increases rapidly as orders decrease below three hundred packages. Knowing the revenue obtained for doing the work, it is a simple matter to determine from the curve the smallest size of order of this commodity which can be handled under average conditions without incurring a loss. If the revenue for Fig. 159 were 1.5 cents per package it could be seen at once that (since the overhead expenses are not considered) there must certainly be a dead loss on orders containing less than sixty-five packages each. If the overhead expenses are taken into account as well as direct labor, there would be shown a loss on orders of larger size, probably up to one hundred or one hundred and fifty packages. Assuming that a loss occurs on all orders shown on Fig. 159 up to the size of one hundred and fifty packages per order, the number of dots to the left of the line for 150 on the horizontal scale indicates just how great the total monetary loss would be.

Curve "A" in Fig. 159 shows the percentage of orders which contain more than any specified number of packages selected on the horizontal scale of the chart. Curve "B" shows the percentage of the total packages which are found in orders containing more than any specified number of packages selected on the horizontal scale of the chart. Curve "A" indicates the amount of clerical work involved, and curve "B" shows the amount of actual labor and the amount of revenue in exactly the same manner described for Figures 157 and 158.