The best form of documentation is a recording, either audio or video. These are cheap and easy to make but difficult to store. Medical records departments are equipped to store flat, relatively indestructible materials; lumpy items get lost or destroyed. This will change as medical images start being stored electromagnetically, but for the near future, the storage problems for recordings are a major impediment to their use. For this reason, recordings should be used only when the medical procedure or the patient poses particular problems. Unusual treatments include heart or liver transplants, experimental heroic measures such as artificial hearts, or refusal of lifesaving treatment by salvageable young people. Problem patients include minors undergoing nontherapeutic procedures (such as kidney donors), involuntary patients such as prisoners, patients with transient mental disabilities, and others for whom their state of mind at the time may become a significant issue.

When the person is illiterate but speaks and understands English, consent is usually documented with a witness. Ideally, this should be an impartial witness. The problem with an impartial witness is finding one. A family member may remember only what the patient remembers, whereas a nurse will be seen as an interested party. Clergy, a volunteer from a service agency, or another person not clearly identified with either the physician or the patient is the best choice. The witness must be present at the discussion with the patient and must make some independent record of his or her observations. This independent record may be simply initialing sections of the consent form or a note that certifies that the patient was asked a given question and made the appropriate reply.