Open File Discovery
Open file discovery is promoted in the United States as a means to help equalize the investigatory disparity between the prosecution and the defense attorney.  Under open file discovery, a defendant should have access to the prosecutor's entire file and there should never be any surprises at trial.
Open file discovery is also the only means by which the state can guarantee due process to defendants. It also eliminates the need for prosecutors to evaluate whether evidence is both material and exculpatory under the Brady Rule.
Disclosure must not only be complete, it must also be timely. Disclosure must be completed well in advance of trial so that the defense attorney has time to examine the evidence, test it, and prepare an adequate defense.
Example of Open File Discovery Statute from North Carolina
� 15A?903. Disclosure of evidence by the State - Information subject to disclosure.
(a) Upon motion of the defendant, the court must order the State to:
(1) Make available to the defendant the complete files of all law enforcement and prosecutorial agencies involved in the investigation of the crimes committed or the prosecution of the defendant. The term "file" includes the defendant's statements, the codefendants' statements, witness statements, investigating officers' notes, results of tests and examinations, or any other matter or evidence obtained during the investigation of the offenses alleged to have been committed by the defendant. The term "prosecutorial agency" includes any public or private entity that obtains information on behalf of a law enforcement agency or prosecutor in connection with the investigation of the crimes committed or the prosecution of the defendant. Oral statements shall be in written or recorded form, except that oral statements made by a witness to a prosecuting attorney outside the presence of a law enforcement officer or investigatorial assistant shall not be required to be in written or recorded form unless there is significantly new or different information in the oral statement from a prior statement made by the witness. The defendant shall have the right to inspect and copy or photograph any materials contained therein and, under appropriate safeguards, to inspect, examine, and test any physical evidence or sample contained therein.
(2) Give notice to the defendant of any expert witnesses that the State reasonably expects to call as a witness at trial. Each such witness shall prepare, and the State shall furnish to the defendant, a report of the results of any examinations or tests conducted by the expert. The State shall also furnish to the defendant the expert's curriculum vitae, the expert's opinion, and the underlying basis for that opinion. The State shall give the notice and furnish the materials required by this subsection within a reasonable time prior to trial, as specified by the court.
(3) Give the defendant, at the beginning of jury selection, a written list of the names of all other witnesses whom the State reasonably expects to call during the trial. Names of witnesses shall not be subject to disclosure if the State certifies in writing and under seal to the court that to do so may subject the witnesses or others to physical or substantial economic harm or coercion, or that there is other particularized, compelling need not to disclose. If there are witnesses that the State did not reasonably expect to call at the time of the provision of the witness list, and as a result are not listed, the court upon a good faith showing shall allow the witnesses to be called. Additionally, in the interest of justice, the court may in its discretion permit any undisclosed witness to testify.
(b) If the State voluntarily provides disclosure under G.S. 15A?902(a), the disclosure shall be to the same extent as required by subsection (a) of this section.
(c) Upon request by the State, a law enforcement or prosecutorial agency shall make available to the State a complete copy of the complete files related to the investigation of the crimes committed or the prosecution of the defendant for compliance with this section and any disclosure under G.S. 15A?902(a). (1973, c. 1286, s. 1; 1975, c. 166, s. 27; 1983, c. 759, ss. 1?3; 1983, Ex. Sess., c. 6, s. 1; 2001?282, s. 5; 2004?154, s. 4; 2007?183, s. 1; 2007?377, s. 1; 2007?393, s. 1.)