RPMs are effective for one year (and can be extended for one year), after which the policies published in RPMs should be incorporated into permanent policy. Regional policy cannot conflict with or supersede national policy. RPMs convey instructions regarding compliance, and establish roles and responsibilities for IA employees within the jurisdiction of a Regional Office.

Regional Policy Memoranda (RPM) adapt interim policy to circumstances unique to particular regions. National policy is established or amended only in writing and only by the Assistant Secretary, the Deputy Assistant Secretaries, the Director, BIA, or the Director, BIE. The NPM document must be read in order to understand some of the effective and expired dates. In some cases, the 'expired' date is different than one might expect. The signature date is typically the 'issued' (effective) date. There have been some discrepancies in the past regarding the review and sign-off on NPMs and the recording of 'effective' and 'expired' dates.

Only two extensions ('amendments') are allowed before the NPM must be converted to an IAM or allowed to expire. At that time, the NPM can be extended for another year (also referred to as an 'amendment') converted to permanent policy (IAM chapter) or allowed to simply expire. An NPM is valid for one year, after which it must be evaluated for relevance. National Policy Memoranda (NPM) provide interim instructions regarding the official duties and responsibilities of IA employees.

Memorandum or memoranda