Both Senators and Representatives must ask the consent of their chamber if they wish to revise, or to extend, their remarks in the Congressional Record. This is because regulations of the Joint Committee on Printing, which supervises the Government Printing Office, limit revisions of the words actually spoken on the floor to grammatical or technical changes only. So, if Members wish to insert the full text of an editorial, article, or letter to accompany the statement they made on the floor, they must get permission to "extend" their remarks. If they wish to make permitted marginal changes to their statement, they must get permission to "revise" their remarks. Most Members, mostly out of habit, ask for permission to "revise and extend" their remarks simply to cover all possibilities.

Congressional Record clerks have observed that very few Members today substantively revise their remarks, although a lot of them do extend them. With C-SPAN coverage, widespread use of videotape recorders, and public and press witnesses in the galleries for each floor session, it would be extremely unlikely that withdrawing or changing controversial remarks would go unnoticed. However, Members still sometimes seek to substantively revise their remarks because (1) they regret something they said and wish it to be deleted from the permanent record, or (2) they might wish they had said something they forgot to say or had ran out of allotted time to say. Substantive revisions technically require the consent of the chamber, although what is substantive may come down to the judgment of the clerk on duty at the time.

Rules require that the Congressional Record be "substantially" verbatim, rather than totally verbatim. And, in fact, it is more verbatim today than ever before in congressional history. For the first 90 years of Congress, outside reporters were hired to keep a record of the floor proceedings. First called the Annals of Congress, and then later the Congressional Globe, its reporters were not always accurate in their descriptions, often lapsing into rather colorful characterizations of the goings-on. After the Civil War, Congress hired its own clerks to keep a Congressional Record of the proceedings.

Despite the professionalism of the new institutional employees, the difficulty of hearing every word above the noise on the floor made total accuracy impossible. Prior to the advent of electronic sound systems, many Members complained that their words had not been accurately reported. Even today, while the audio equipment allows viewers to hear the proceedings clearly, those physically on the floor often cannot hear either the Chair or the Member speaking. The floor is the one place where Members all gather together at the same time, and all the greetings, cajoling, and conversations can create quite a hub-bub. That's why it sometimes takes the Chair a long time and a heavy hand with the gavel to get order.