Copyright law protects the owners of copyright from unauthorized copying or use of their creative works.  There are certain exceptions in the copyright law like statutory or compulsory license which allows a person to use a copyrighted work without the explicit permission of its owner.  In such cases, law sets up agency or a specific body to negotiate and collect royalty for the work used by way of statutory license.

Royalties are payments made to the owner of an asset by its user for an ongoing usage of the asset.  Copyright royalties are specific to the usage of copyrighted creative works like books, music and so on.  Royalties are generally a percentage of revenue generated from the use of the work.

The Copyright Arbitration Royalty Panels (CARP) was a part of U.S. Copyright Office.  CARP, which replaced Copyright Tribunal in 1993, was a system consisted of ad hoc arbitration panels.  It suggested the royalty rates and allocation of royalty fees collected under of the statutory licenses.  It also set terms and conditions of some of the statutory licenses.

With the enactment of the Copyright Royalty and Distribution Reform Act of 2004 on Nov. 30, 2004, the Copyright Arbitration Royalty Panel (CARP) system was replaced with a system of the Copyright Royalty Board (CRB).  Now, CRB takes care of collection and distribution of the royalties of copyright statutory licenses.  The Board is made up of three copyright royalty judges.  These judges are appointed by the Librarian of Congress.