The primary purpose of the authority codes is to identify expenditure transactions for accountability and reporting in the Public Accounts of Canada according to the specific votes and other authorities in the Estimates, other authorities included in specific statutes; and in addition, to identify the nature of revenue, by tax and non-tax revenue. Other authority codes (non-appropriated authorities) are also established by central agencies to facilitate the identification of various accounting transactions that do not require the use of appropriations. An appropriation is an authority of Parliament to pay money out of the Consolidated Revenue Fund (CRF) and as such, provides parliamentarians with control over most expenditures of the government. As a general rule, transactions are recorded against an appropriation on an expenditure basis; however, there are certain expenditures that are not charged to an appropriation until a payment is required. The authority code identify expenditures transactions as follows: Statutory expenditures Statutory expenditures are those that Parliament has approved through legislation (other than Appropriations Act) that set out the purpose of the expenditures and the terms and conditions under which they may be made. Non-statutory expenditures are those that Parliament approves annually through an Appropriation Act. Once approved the vote wording and the expenditure authority attributable to each vote become the governing conditions under which these expenditures may be made. Non-appropriated transactions Non-appropriated authority codes identify accounting transactions that do not require the use of appropriations (i.e., expenditure or revenue are already recognized [e.g., amortization expense or the receipt of revenue credited to vote] or expenditure is not charged to appropriations until the payment is required [e.g., severance pay]).