Discovery

Each party initially learns the facts of the case through its personal knowledge and investigation. As the trial approaches, a set of procedures, commonly called discovery, permit each side to require disclosure of certain aspects of the opponent's evidence. Whether in civil or criminal cases, the purposes of pretrial discovery are generally the same. Discovery of the opponent's case is thought to further the truth-seeking function of trials by avoiding surprise, sometimes colorfully called "trial by ambush." In addition, early disclosure of the strengths and weaknesses of the case facilitates negotiated settlement and, where appropriate, dismissal of baseless charges. Because discovery facilitates efficiency in litigation, it is believed to save resources.

Discovery in American courts is much less extensive in criminal cases than in civil, and it is somewhat asymmetrical in that greater discovery is provided for the defense than for the prosecution. These features are likely related to each other and each is in part a consequence of the constitutional rights protecting the criminal accused. Criminal discovery has, nevertheless, greatly expanded in the last third of the century. Expansion first concerned principally defense discovery from the prosecution, but in the last several decades, discovery from the defense has grown dramatically. The development and expansion of what is called reciprocal discovery—discovery provided to both defense and prosecution—is central to the considerable growth of discovery in criminal cases.

Interestingly, the federal system is not at the cutting edge of developments in criminal discovery. Instead, the movement has been led by the states, and it is perhaps the difficulty of tracking developments that occur in so many different jurisdictions that has resulted in relatively little attention being paid to the reasonably major changes in this field of criminal procedure.