In order to determine the value of the work completed at any one of these stated periods, some method of evaluation of the various component parts of the work must be agreed upon. A very simple and satisfactory method is to request the contractor to break down his contract price into a number of items, perhaps twenty in all, such as excavation, concrete of the various classifications, brick work, tile work, plumbing, heating, electrical work, roofing, painting, etc. With these items evaluated in proportionate values, the total equaling 100 per cent of the contract price taken in connection with the quantities of materials and labor in each, which the constructing quartermaster can check, it is not an involved process to compute the amount due the contractor at the end of any period. The new contract form wisely permits credits to contractors for material delivered on the site, but not yet installed in the building. This is a sensible provision, but consideration must be given by the constructing quartermaster to the character of the various items.
Fabricated steel is in a different category from cement, for instance.
One is practically indestructible, while the other may be spoiled by exposure. All construction contracts are drawn up in the field, but are signed by the Chief of the Construction Service as contracting officer. The reason for this recent change in policy is the new Interdepartmental Form of Contract, which gives authority to the contracting officer to make change orders. These became such a problem that it was deemed best to retain such authority in the Office of The Quartermaster General. Incidentally, these change orders referred to take the place of the old supplemental agreements.