Any evidence which is sufficiently reliable and probative to support a decision under the provisions of the Administrative Procedure Act, or which would be admissible under the general statutes of the United States, or under the rules of evidence governing proceedings in matters not involving trial by jury in the courts of the United States, will be admissible in hearings before the Board. The rules of evidence will be applied in any proceeding to the end that necessary and proper evidence will be conveniently, inexpensively, and speedily produced, while preserving the substantial rights of the parties.

An official record or an entry therein, when admissible for any purpose, may be evidenced by an official publication thereof or by a copy attested by the officer having the legal custody of the record, or by a deputy, and accompanied with a certificate that such officer has the custody. If the office in which the record is kept is within the United States or within a territory or insular possession subject to the dominion of the United States, the certificate may be made by a judge of a court of record of the district or political subdivision in which the record is kept, authenticated by the seal of the court, or may be made by any public officer having a seal of office and having official duties in the district or political subdivision in which the record is kept, authenticated by the seal of his office. If the office in which the record is kept is in a foreign state or country, the certificate may be made by a secretary of embassy or legation, consul general, consul, vice consul, or consular agent or by officer in the foreign service of the United States stationed in the foreign state or country in which the record is kept, and authenticated by the seal of his office. A written statement signed by an officer having the custody of an official record or by his deputy that after diligent search no record or entry of a specified tenor is found to exist in the records of his office, accompanied by a certificate as above provided, is admissible as evidence that the records of this office contain no such record or entry. This section does not prevent the proof of official records or of entry or lack of entry therein or official notice thereof by a method authorized by any applicable statute or by the rules of evidence.

Any writing or record, whether in the form of an entry in a book or otherwise, made as a memorandum or record of any act, transaction, occurrence, or event, will be admissible as evidence thereof if it appears that it was made in the regular course of business, and that it was the regular course of business to make such memorandum or record at the time such record was made, or within a reasonable time thereafter.

If a party offers in evidence any matter contained in a report or other document open to public inspection in the files of the Board, such report or other document need not be made available at the hearing.

If any portion of the record before the Board in any proceeding other than the proceeding at issue is offered in evidence, a true copy will be presented for the record.

The Board or a hearing officer may take notice of official records, records in other Board proceedings, or other materials which are otherwise subject to specific rules governing admissibility regardless of compliance with the full technical provisions of such rules, where the admissibility of the evidence is for purposes of corroboration of testimony presented or to evaluate the credibility of testimony or allegations made in proceedings where the public interest is not otherwise adequately represented by counsel capable of fully complying with such rules.

Whenever practical the sheets of each exhibit and the lines of each sheet should be numbered. If the exhibit consists of five or more sheets, the first sheet or title-page should be confined to a brief statement of what the exhibit purports to show with reference by sheet and line to illustrative or typical examples contained therein. The exhibit should bear an identifying number, letter, or short title which will readily distinguish it from other exhibits offered by the same party. It is desirable that, whenever practicable, evidence should be condensed into tables. Whenever practicable, especially in proceedings in which it is likely that many documents will be offered, all the documents produced by a single witness should be assembled and bound together, suitably arranged and indexed, so that they may be identified and offered as one exhibit. Exhibits should not be argumentative and should be limited to statements of facts, and be relevant and material to the issue, which can better be shown in that form than by oral testimony.