Statutory authority provided by an Act of Congress that permits Federal agencies to incur obligations and make payments from the Treasury. An appropriation usually follows enactment of authorizing legislation. An Appropriation Act is the most common means of providing Budget Authority (BA). Appropriations do not represent cash actually set aside in the Treasury; they represent limitations of amounts that agencies may obligate during the time specified in the respective appropriation. Major appropriation types are listed below:
Research, Development, Test, and Evaluation (RDT&E) appropriations fund the efforts performed by contractors and government activities required for the research and development (R&D) of equipment, material, computer application software, and its Test and Evaluation (T&E) including Initial Operational Test and Evaluation (IOT&E) and Live Fire Test and Evaluation (LFT&E). RDT&E also funds the operation of dedicated R&D installation activities for the conduct of R&D programs.
Procurement appropriations fund those acquisition programs that have been approved for production (to include Low Rate Initial Production (LRIP) of acquisition objective quantities), and all costs integral and necessary to deliver a useful end item intended for operational use or inventory upon delivery.
Operation and Maintenance (O&M) appropriations fund expenses such as civilian salaries, travel, minor construction projects, operating military forces, training and education, depot maintenance, stock funds, and base operations support.
Military Personnel (MILPERS) appropriations fund costs of salaries and other compensation for active and retired military personnel and reserve forces based on end strength.
Military Construction (MILCON) appropriations fund major projects such as bases, schools, missile storage facilities, maintenance facilities, medical/dental clinics, libraries, and military family housing.