U.S. Dep't of Defense, Instruction No. 5025.01, Part II (Oct. 28, 2007)
DoDI. DoDIs consist of the following two levels of issuances. DoDIs shall be no more than 50 pages in length including enclosures. (1) Policy DoDI: A DoDI that ESTABLISHES POLICY and assigns responsibilities within a functional area assigned in the Head of an OSD Component’s chartering DoDD, including defining the authorities and responsibilities of a subordinate official or element when these do not meet the criteria for a chartering DoDD. Policy DoDIs may also provide general procedures for implementing that policy. They shall be signed by the Heads of the OSD Components. They shall include the Component’s chartering DoDD as a reference, and, for the Components whose chartering DoDDs have NOT been updated to include the authority to issue policy in DoDIs, they shall include this Instruction as a reference. (2) Non-Policy DoDI: A DoDI that IMPLEMENTS POLICY established in a DoDD by providing general, overarching procedures for carrying out that policy. Non-policy DoDIs shall be signed by the Heads of the OSD Components, their Principal Deputies, or the OSD PAS officials as authorized by their chartering DoDDs.