5 C.F.R. § 1201.4 : Administrative Personnel — MERIT SYSTEMS PROTECTION BOARD — ORGANIZATION AND PROCEDURES — PRACTICES AND PROCEDURES — JURISDICTION AND DEFINITIONS — General definitions

(a) Judge. Any person authorized by the Board to hold a hearing or to decide a case without a hearing, including the Board or any member of the Board, or an administrative law judge appointed under 5 U.S.C. 3105 or other employee of the Board designated by the Board to hear such cases, except that in any case involving a removal from the service, the case shall be heard by the Board, an employee experienced in hearing appeals, or an administrative law judge.
(b) Pleading. Written submission setting out claims, allegations, arguments, or evidence. Pleadings include briefs, motions, petitions, attachments, and responses.
(c) Motion. A request that a judge take a particular action.
(d) Appropriate regional or field office. The regional or field office of the Board that has jurisdiction over the area where the appellant's duty station was located when the agency took the action. Appeals of Office of Personnel Management reconsideration decisions concerning retirement benefits, and appeals of adverse suitability determinations under 5 CFR part 731, must be filed with the regional or field office that has jurisdiction over the area where the appellant lives. Appendix II of these regulations lists the geographic areas over which each of the Board's regional and field offices has jurisdiction. Appeals, however, may be transferred from one regional or field office to another.
(e) Party. A person, an agency, or an intervenor, who is participating in a Board proceeding. This term applies to the Office of Personnel Management and to the Office of Special Counsel when those organizations are participating in a Board proceeding.
(f) Appeal. A request for review of an agency action.
(g) Petition for review. A request for review of an initial decision of a judge.
(h) Day. Calendar day.
(i) Service. The process of furnishing a copy of any pleading to Board officials, other parties, or both, by mail, by facsimile, by commercial or personal delivery, or by electronic filing (e-filing) in accordance with §1201.14.
(j) Date of service. "Date of service" has the same meaning as "date of filing" under paragraph (l) of this section.
(k) Certificate of service. A document certifying that a party has served copies of pleadings on the other parties or, in the case of paper documents associated with electronic filings under paragraph (h) of §1201.14, on the MSPB.
(l) Date of filing. A document that is filed with a Board office by personal delivery is considered filed on the date on which the Board office receives it. The date of filing by facsimile is the date of the facsimile. The date of filing by mail is determined by the postmark date; if no legible postmark date appears on the mailing, the submission is presumed to have been mailed five days (excluding days on which the Board is closed for business) before its receipt. The date of filing by commercial delivery is the date the document was delivered to the commercial delivery service. The date of filing by e-filing is the date of electronic submission.
(m) Electronic filing (e-filing). Filing and receiving documents in electronic form in proceedings within the Board's appellate or original jurisdiction in accordance with §1201.14.
(n) E-filer. A party or representative who has registered to engage in e-filing under paragraph (e) of §1201.14.
(o) Grievance. A complaint by an employee or labor organization under a negotiated grievance procedure covered by 5 U.S.C. 7121.
(p) Substantial evidence. The degree of relevant evidence that a reasonable person, considering the record as a whole, might accept as adequate to support a conclusion, even though other reasonable persons might disagree. This is a lower standard of proof than preponderance of the evidence.
(q) Preponderance of the evidence. The degree of relevant evidence that a reasonable person, considering the record as a whole, would accept as sufficient to find that a contested fact is more likely to be true than untrue.
(r) Harmful error. Error by the agency in the application of its procedures that is likely to have caused the agency to reach a conclusion different from the one it would have reached in the absence or cure of the error. The burden is upon the appellant to show that the error was harmful, i.e., that it caused substantial harm or prejudice to his or her rights.
(s) Nonfrivolous allegation. A nonfrivolous allegation is an assertion that, if proven, could establish the matter at issue. An allegation generally will be considered nonfrivolous when, under oath or penalty of perjury, an individual makes an allegation that:
(1) Is more than conclusory;
(2) Is plausible on its face; and
(3) Is material to the legal issues in the appeal.

5 C.F.R. § 1201.4

54 FR 53504, 12/29/1989, as amended at 58 FR 36345, 7/7/1993; 59 FR 65235, 12/19/1994; 68 FR 59860, 10/20/2003; 69 FR 57628, 9/27/2004; 73 FR 10129, 2/26/2008; 77 FR 62364, 10/12/2012; 80 FR 4496, 1/28/2015