Discovery

The availability of defense discovery of witness names and their statements is a feature that distinguishes discovery systems. Neither type of information is provided in discovery in federal courts, illustrating the fact that the federal system is not at the forefront of expansive criminal discovery, but many states provide both categories of discovery to defendants. States often also require that the defense provide similar information to the prosecution.

Resistance to disclosure in federal cases of witness names and statements may be explained by more frequent federal prosecution of cases involving organized crime and large criminal enterprises where the prospect of witness tampering is predictably greater. Federal authorities have never accepted that protective orders, which allow courts upon a showing of special need to impose limits on discovery, would be a sufficient protection. The concern is that even though dangers of tampering exist, prosecutors may be unable to support their request for a protective order with sufficient objective evidence of this danger.

The 1970 ABA Discovery Standards supported the disclosure to the defense of witness names and statements. As noted earlier, it also supported a right of the prosecution to obtain a list of defense witnesses as well as a specification of all defenses supported by such witnesses. A substantial number of states adopted some part of this expansive discovery system, and many of these require the defense to provide the prosecution with statements of defense witnesses as well. To facilitate disclosure, many of these states also remove the protection against disclosure of witness statements that is frequently found in the work product doctrine. By contrast, the federal system continues to prohibit discovery of witness statements through longstanding legislation, commonly called the "Jencks Act," which prohibits required pretrial discovery of such statements but mandates their production for defense use in cross-examination and impeachment at the conclusion of the witness' direct examination.

One growing trend in criminal discovery is to require the preparation of a summary of a witness' testimony to be produced during discovery if a statement by the witness does not already exist. This requirement may be imposed on the defense and the prosecution alike. Preparation of such statements is required for all witnesses in some states, and it has been adopted, even in the federal courts, for expert witnesses. For expert witnesses in federal cases, both parties are required to provide their adversary with a written summary of the testimony of expert witnesses, which includes a description of the opinion, its basis, and the expert's qualifications.