As the size and scope of federal government activities increased during the nineteenth and early twentieth centuries, the congressional practices related to authorizations and appropriations began to change. Second, associated with these provisions, these committees began to conduct reviews and enact revisions to authorization laws for certain agencies and departments on periodic schedules, instead of on an as-needed basis. In response, the legislative committees began to explore new legislative language that would influence budgetary outcomes, both with respect to the action of the appropriators, and also in their oversight of the agencies under their jurisdiction. Emergence of Explicit Authorizations of Appropriations

The first significant change in the form of authorization laws occurred after the 1920s, when authorization laws began to include provisions that explicitly "authorized to be appropriated" future budgetary resources tied to certain purposes. The types of provisions periodically authorizing appropriations that were developed during this period have continued to be used through the present day. These provisions generally indicate two schedules of legislative review: "annual" and "multiyear." Annual authorizations of appropriations explicitly authorize appropriations for a single fiscal year. Multiyear authorizations of appropriations explicitly authorize appropriations for more than one fiscal year at a time (typically between two and five). The proportion of agencies that were subject to annual reauthorizations expanded significantly during the mid-twentieth century. Changes to Authorizations of Appropriations in Practice: Selected Examples

The historical development of the form and timing of authorizations over the past century has been characterized by a number of themes: 
The legislative committee's adoption of an annual reauthorization schedule was due to a desire for increased involvement in both agency and congressional budgetary decisions. Annual authorizations tended to be characterized by incremental program changes, whereas multiyear authorizations tended to involve widespread policy changes. The amounts authorized in annual measures tended to be more similar to the amount eventually appropriated when compared to multiyear authorizations. The out-years of multiyear authorizations tended to be characterized by a growing gap between the amount authorized and amount appropriated. To illustrate one or more of these general themes, the following subsections summarize aspects of the authorization histories of the National Science Foundation, the National Aeronautics and Space Administration, and the Peace Corps. These case studies also discuss the reasons for the shifts to the new authorization schemes, such as the legislative committee's decision to review and make policy changes to the program on a less frequent schedule, or difficulties in enacting annual authorizations prior to appropriations. In addition, until the enactment of P.L. As the NSF and NASA transitioned to a more long-term reauthorization schedule over the past thirty years, their reauthorization laws have become more policy-focused and contained more instances of significant program changes.
The congressional budget process distinguishes between "authorizations," which establish or define the activities of the federal government, and "appropriations," which finance those activities. The purpose of this report is to discuss the changes in the form and frequency of authorization laws that have occurred over the past century.
As the congressional approach to authorizations and appropriations developed over the nineteenth century, distinct roles for these types of laws were established. However, that approach began to shift in the early twentieth century as the size and scope of federal government activities increased, and the legislative committees began to explore new methods of influencing budgetary outcomes, both with respect to the action of the appropriators and for the agencies under their jurisdiction. Toward that end, those committees began to include provisions that explicitly authorized appropriations in authorization acts. In addition, these committees began to use these provisions to establish periodic schedules of review for revisions to authorization laws for certain agencies and departments, instead of enacting such laws on an as-needed basis.
The types of provisions periodically authorizing appropriations that were developed during the mid-twentieth century have continued to be in use through the present day. Such provisions can generally be divided into two schedules of review: "annual" and "multiyear." Annual authorizations of appropriations explicitly authorize appropriations for a single fiscal year. Multiyear authorizations of appropriations explicitly authorize appropriations for more than one fiscal year at a time, typically between two and five of them.
The evolution of the form and frequency of authorizations since the 1920s have been characterized by a number of general themes. Annual reauthorization schedules were often adopted due to the legislative committee's desire for increased involvement in agency and congressional budgetary decisions. Annual authorizations tended to be characterized by more incremental program changes, whereas multiyear authorizations tended to involve more widespread policy changes. Over the past thirty years many agencies on annual schedules have been transitioned to multiyear or long-term schedules. These transitions have often been motivated by delays in the enactment of annual authorizations each year, or the legislative committee's decision to conduct more extensive reviews of agency programs and policies on a less frequent schedule. The amounts annually authorized have tended to be more similar to the amount eventually appropriated when compared to multiyear authorizations. In particular, the outyears of multiyear authorizations have tended to be characterized by a growing gap between the amount authorized and amount appropriated.
To illustrate the themes identified in the first section of the report, the second section describes aspects of the authorization histories of the National Science Foundation, the National Aeronautics and Space Administration, and the Peace Corps. In general, all three of these agencies experienced eras of annual reauthorization, and then most recently transitioned to a more long-term or intermittent schedule.