While less formal than trials, arbitration practice involves the use of some specialized vocabulary.  To assist the reader with understanding those terms, we have created a glossary of arbitration terms.


Adverse Witness: A representative of one party to an arbitration who is called as a witness by the opposing party, as when a grievant is called by an employer or a supervisor is called by a union. Being considered an adverse witness means that the cross- examination format can be used in asking questions, including the use of leading questions. Sometimes referred to as a hostile witness.

Advocate: A person representing the grievant(s) or the employer who presents the grievant’s or employer’s position, evidence, and arguments to an arbitrator.  The advocate may be an attorney specializing in labor law but may also be a union representative (for the grievant) or labor relations specialist (for the employer).

Appeal: The act of taking an arbitration award to court with the goal of overturning or modifying the arbitrator’s decision.  The judicial grounds for overturning an award are very limited but may include such questions as legality of the award, enforceability of the award, or impartiality of the arbitrator.

Affidavit: A written statement or declaration offered as a sworn document about a matter at issue. Arbitrators at times will permit the submission of an affidavit but almost never treat the statement alone as proof of the facts stated in the document.

Arbitrability: The arbitrator’s jurisdiction or authority to hear a case. Substantive arbitrability objections involve whether or not the subject matter of the dispute is within the scope of arbitration. Procedural arbitrability claims involve whether or not conditions have been satisfied for the arbitration to go forward. Substantive arbitrability objections typically are reserved for judicial determination unless a labor agreement or the parties in a specific case confer such authority on an arbitrator. A presumption of arbitrability often is imposed by the final decision maker. Procedural arbitrability objections usually involve issues of contractual time limits or other terms that are decided by an arbitrator, not a court. In some instances arbitrability issues are bifurcated for a decision to be rendered before the merits of the dispute are argued.

Arbitral Notice: When an arbitrator takes notice of statutes, case law, government regulations, or other facts of common and widespread knowledge whose accuracy is not reasonably subject to dispute. The party requesting notice be taken need not establish a formal evidentiary basis for the fact subject to notice. Also called judicial notice.

Arbitration: A method of dispute resolution provided by a collective bargaining agreement or other contract, typically with a final and binding decision to be rendered by an impartial decision maker known as an arbitrator. The predominant form of arbitration in labor matters is grievance arbitration, also known as rights arbitration. Another type is interest arbitration, which is used to resolve an impasse or deadlock during bargaining in the formation of a contract or one of its provisions. Arbitration that is not final and binding is known as advisory arbitration.

An arbitration decision includes an award setting forth the specific order of the arbitrator. When upheld in court, an award is confirmed. Under narrow circumstances an award may be vacated or overturned, often with a court deciding to remand the case to the arbitrator for further activity.

The arbitrator may be selected on an ad hoc or case-by-case basis. Or the arbitrator may be selected from a permanent panel of arbitrators agreed to by the parties to a labor agreement. Selections also can be made by parties striking names from a list transmitted by an administrative agency of provider organization such as the Federal Mediation and Conciliation Service or the American Arbitration Association.

Arbitration that is mutually adopted by the parties during collective bargaining differs from mandatory arbitration agreements demanded by some employers for their employees in non-union workplaces as an alternative to civil litigation.


Back pay: Wages required to be paid an employee upon an arbitrator’s finding that a discharge or layoff of an employee was not for just cause or was in violation of the employee’s contractual or statutory rights.

Bargaining unit: A grouping of employment positions or classifications that share a community of interest in a workplace. A bargaining unit is represented by a union in negotiations and during contract administration. The union that represents employees in a bargaining unit is known as the bargaining agent or exclusive representative.

Bench decision: An oral ruling rendered by an arbitrator after a hearing on an arbitrability issue or on the merits of the case.

Best evidence: Primary evidence, usually in the form of a writing, rather than secondary evidence or copies.

Bifurcation: Dividing a labor arbitration hearing to permit the separate consideration of arbitrability questions and the merits of the case. Bifurcation also may refer to separating the liability phase of a case from a subsequent determination of specific monetary amounts, as when a make-whole relief is awarded and the arbitrator retains jurisdiction over later disputes that emerge about financial calculations.

Brief: A written summary of facts and legal principles related to a dispute. A post- hearing brief often is used instead of a closing statement (or closing argument) at the conclusion of a hearing. Some parties also file briefs in lieu of opening statements at the outset of a hearing.

Bumping: A procedure permitting a worker subject to layoff, transfer, or other contractual action the right to displace a worker with less seniority.

Burdens: The burden of going forward refers to the party with the obligation to present evidence first on a matter in dispute. The phrase “burden of proof,” or “burden of persuasion,” refers to the ultimate obligation to demonstrate sufficient evidence borne by one of the parties. Burdens may apply to particular issues as well as to the case as a whole. In disputes involving contract interpretation the burden typically rests with the union as the grieving party. In contrast, in disciplinary matters the burdens of going forward and proof typically are assigned to the employer as the party altering the status quo. The allocation of burdens also applies to particular issues such as arbitrability and affirmative defenses (for example, the burden to demonstrate untimely grievances, negotiation waivers, disparate treatment, mitigation of damages, etc.).


Cease-and-desist order: A directive in an award requiring a party that violated a labor agreement to halt the offending practice in the future.

Charge: A written statement alleging an employee’s misconduct.

Circumstantial evidence: Evidence which involves facts that, when taken together, establish another fact by the circumstances and inferences drawn from the factual connections.

Class action: An action in which two or more employees with a common interest file a grievance on behalf of themselves and all similarly-situated employees.

Collateral estoppel: A doctrine barring evidence about a fact or issue that was subject to prior adjudication from being offered in a subsequent arbitration. This concept is similar to, but different from, res judicata, which involves a contention that the case (and dispute itself) has been the subject of previous resolution and cannot be tried anew. Both principles differ from double jeopardy, a concept borrowed from criminal law that precludes an employer from seeking to discipline an employee twice for the same misconduct.

Collective bargaining: The negotiation by an employer and a bargaining agent of terms and conditions of employment governing the members of a bargaining unit. When successful, their bargaining results in a collective bargaining agreement. In some industries multi-employer or multi-union (or coalition) bargaining is used, leading to a master agreementcovering all affected parties. Master agreements may have local supplements for particular employers or geographic areas. In the public sectors the phrase meet and confer often refers to the negotiating process resulting in a memorandum of understanding (or MOU).

Concerted activity: Employee activity in association with others that usually involves union organizing, protesting employer conduct, or asserting other mutual aid and protection.

Consent award: An arbitration order agreed upon by the parties.

Cumulative evidence: Involves the repetitive presentation of testimony regarding the same matter.


Damages: A sum of money recovered to redress or make amends to a grievant for the wrong done.  In most cases an arbitrator will award only such monies as make the wronged employee whole – i.e., place the employee in the financial position he/she would have been in but for the wrong done.

Deferral:  policy of the National Labor Relations Board and many public sector labor boards to delay administrative action until an arbitration is completed. An arbitrator’s decision then may be reviewed by a labor board to determine if it is repugnant or significantly at odds with labor relations law.

Demeanor: The physical attributes of a witness when testimony is being offered, including gestures, tone of voice, and general appearance. A witness’s demeanor may be a factor in assessing credibility, although these observations usually will not be determinative.

Deposition: The testimony of a witness taken outside the arbitration hearing before a person authorized to administer oaths.

Direct Evidence: Evidence is offered as proof of a fact without relying on any inference or presumption.

Direct examination: Questions posed to a witness who has been called by a party. Cross-examination involves questions posed by the party who did not call the witness. The initial round of witness testimony is followed by redirect or recross examination.

Disclosure responsibilities (or an arbitrator): An arbitrator should be aware of any potential or perceived conflict of interest that may arise.  Prior to accepting an appointment, an arbitrator must make the parties aware of any current or past relationship with any party involved in the arbitration, regardless of whether the nature of that relationship is professional or personal.  Similarly, an arbitrator has an obligation to disclose any financial interest in the arbitration or with any party. If an arbitrator accepts an appointment and later becomes aware of a potential conflict of interest, disclosure must be made at that time.  An arbitrator should disclose any circumstance that might reasonably raise a question as to the arbitrator’s impartiality.

Discovery: The formal process of gathering information or evidence prior to a hearing through depositions, requests for documents, written questions or interrogatories, and other methods. Although formal discovery is a common feature of civil litigation, it rarely is used in labor arbitration. In labor cases the parties usually rely on the exchange of information during grievance processing, supplemented by the use of subpoenas to secure additional evidence for the hearing.

Documentary evidence: Evidence which is presented in a writing or document offered as proof.

Due process: Procedural due process is an element of just cause and requires that before an employee may be disciplined, the employer must provide the employee with notice of the charges and an opportunity to be heard.  The scope of protection is broader for employees in the public sector, but employees in the private sector are also generally thought to be entitled to due process protections.  In addition, due process principles may protect an employee from double jeopardy and from interrogation by an employer without union representation when it is requested.  In an arbitration hearing due process means that each party must be given adequate notice of the date, time, and place of the hearing and the opportunity to present evidence and cross-examine the opposing party’s witnesses. Further, the arbitration award must be based on the evidence presented at the hearing.

Duty of fair representation: The obligation of a bargaining agent to represent bargaining unit employees fairly. Arbitrary, discriminatory, or bad faith conduct constitutes a breach of the duty. The duty of fair representation applies to grievance arbitration or negotiation where the union is authorized to act on behalf of unit employees regardless of formal membership in a union.


Evidence: Testimony, writings, or other matters presented as proof at a hearing.

Exhibits: Documents, photos, or other tangible items offered as proof of facts at a hearing. Exhibit items typically are explained by testimony from a witness.

Ex parte communication: Contact by one party with an arbitrator that involves a discussion of the substance or merits of a case.

Expert witness: A witness with specialized knowledge, training, or experience. Expert witnesses are generally permitted to testify on the basis of their opinions.


“Fifth Amendment Rights” in arbitration: The Fifth Amendment to the United States Constitution protects citizens against self-incrimination in criminal trials. Not all arbitrators will extend this right to protect employees from discipline or termination.

Final and binding: A contractual agreement between parties submitting an issue to arbitration that once an award has been issued, its terms are final and binding upon both parties and may be overturned only on very limited grounds.  If either party declines to abide by that award, the opposing party may seek enforcement of the award in a court of law.

Foundation: The term refers to the preliminary facts required to demonstrate the authenticity of a document or the circumstances of testimonial recollections.

Free speech: A constitutional protection that is the basis for employee and employer rights to express certain views.  This right may in some cases be limited by legislation or by the nature of the speech – such as speech that harms the employer’s ability to do business or creates a hostile workplace for an employee.

Front pay: An amount of money awarded a wrongfully treated employee to make the employee whole for the loss of future work opportunities due to the employer’s wrongful treatment.

Functional link (or nexus): Establishment by an employer that an employee’s on- or off-duty conduct likely would (or actually did) adversely impact the employer’s ability to conduct business.  Such a nexus might arise if a uniformed railroad employee dining in a town’s restaurant stated loudly that the railroad going through town did not care about citizens’ safety along the right-of-way. It also could come into play if a disgruntled nurse gossiped negatively about a physician’s competence in front of the doctor’s own patient.


Grievance: A claim by a union or an individual that a term of the contract has been violated. In some settings an employer also can file a grievance. Grievances are processed through an internal grievance procedure that involves a multi-step process that precedes arbitration involving an outside arbitrator. In some industries a board of adjustment that includes representatives of both labor and management is convened before or instead of arbitration involving an impartial arbitrator.

Grievant (Grievor): The individual employee protesting an employer’s actions. An employee may file a grievance on his/her own behalf or the Union may file a grievance on behalf of an individual unless the collective bargaining agreement says otherwise. An arbitration also may involve more than one grievant protesting an employer’s action that impacts all of them.


Hearing: A proceeding before an arbitrator at which parties present evidence and argument prior to a decision. Principles of due process, or basic fairness, apply at hearings, including the right to attend the session, to challenge the claims at issue, to offer testimony and other evidence, and to cross-examine witnesses. Sometimes parties agree to have expedited hearings with limited advance notice, abbreviated testimony, and no post-hearing briefs.

Hearsay evidence: A statement made outside of the arbitration hearing by a person other than the witness who is testifying. It is offered for the truth of the matter contained in the statement. At times, a hearsay statement may include silence as well as conduct. The hearsay rule is subject to many exceptions, such as those for business records and admissions by a party.


Impasse: A situation arising in negotiating a collective bargaining agreement where the parties are unable to make further progress toward reaching an agreement.

Inferences: Logical factual assumptions drawn from direct and circumstantial evidence. This includes the drawings of adverse inferences when a party fails to explain or respond with evidence under its control, such as when a manager is not called as a witness to rebut a claim or when a business record relevant to the dispute is not produced at a hearing.

Injunction: An order of a court of equity to refrain from doing (negative injunction) or to do (affirmative or mandatory injunction) a specified act.  Its use in labor disputes has been greatly restricted by the Norris-LaGuardia Act (1959).

Issue to be decided: Most often, the parties will stipulate (or agree) to the issue to be decided by the arbitrator.  Otherwise, they may give the arbitrator the authority to formulate the issue, or it may be defined by their collective bargaining agreement. An arbitrator only has jurisdiction to decide the issue(s) raised by the parties at the hearing.  Courts have vacated arbitration awards where an arbitrator has gone beyond the issue(s) presented by the parties. 


Jurisdiction of the arbitrator: Authority or jurisdiction of an arbitrator to hear and decide a particular issue placed before him/her in an arbitration hearing. The jurisdiction of the arbitrator’s deliberation is frequently restricted to the issue presented in the original grievance. In other situations the arbitrator’s jurisdiction is limited to either (1) an issue or issues agreed to by the parties to the arbitration, or (2) the authority delegated to the arbitrator to frame the issue.

Just Cause: A phrase applied to assessing an employer’s rationale for disciplining an employee, including such issues as notice of rules, warning of discipline, fairness of the investigation, proof of actual misconduct, and appropriateness of the penalty. Similar terms are good cause, reasonable cause, and sufficient cause.


Laches: A doctrine from the law of equity holding that a party that unjustifiably delays acting on a right for an excessive period of time can lose the opportunity to go forward at a later date. Laches can be asserted even if a contractual time bar was not invoked in the past. It operates on the basis that witnesses with a clear recollection of the facts and pertinent evidence may no longer be available because of the delay in proceeding with a cause of action.

Last-chance agreement: A grievance settlement that allows an individual to return to work, usually without back pay, but specifies that dismissal will be the penalty for any further wrongdoing. Arbitrators sometimes include a proviso in an award stating that a reinstated employee is being given a last chance.

Leading question: Questions which often are used for preliminary matters on direct examination but most commonly are used on cross-examination.


Maintenance of standards: A contract provision preserving previous practices and benefits even if not expressly identified in a successor labor agreement.

Make-whole relief: A remedy providing back pay and benefits to an employee, often offset by interim earnings.

Management rights: A contract clause stating that certain rights are reserved to management unless otherwise specified in the bargaining agreement. Typically, management rights include the specification or assignment of work schedules, duties, job descriptions, operational methods, and production standards, for example.

Materiality: Refers to the the degree of importance of a particular piece of evidence to the matter in dispute.

Mediation: A method of resolving labor disputes whereby a disinterested third party listens to the arguments of both the employer and the union and then suggests methods of reconciling the dispute.  Unlike arbitration, the mediator’s proposed solutions are not binding on either party.

Mediation-arbitration (Med-arb): A procedure agreed upon by the parties that authorizes the same individual to assist the parties in negotiating a settlement as a mediator and thereafter to function as an arbitrator to decide the dispute if a settlement is not reached.


Objections: Objections to evidence are made by an advocate who takes issue with a line of questioning or the introduction of other evidentiary material into the evidentiary record of the hearing. Typical objections are that the testimony is irrelevant, speculative, or hearsay.

Offer of proof: A narrative description of a proposed line of examination presented to an arbitrator when an advocate is seeking to introduce evidence that the opposing party believes is irrelevant. The summary preserves the record in the event the evidence is excluded and an attempt later is made to overturn the award. The same term also applies when seeking to streamline the introduction of witness accounts by permitting a party to stipulate that a witness, if called, would testify consistent with the description set forth in the offer. A party accepting an offer of proof is not agreeing to the truth of the statement but only that the witness would say what is described in the offer if called to testify.

Opinion evidence/Opinion testimony: Opinion evidence involves the belief or impression of a witness about facts in a case. Opinion testimony is in contrast to matters that are known personally to a witness through the physical senses, such as sight, smell, or hearing.


Parol evidence: Describes a verbal discussion or agreement that sheds light on the interpretation of a written agreement.

Past practice: A policy or activity that is consistent, longstanding, known to, and accepted by the parties. Past practice evidence usually is offered to shed light on ambiguous contract language.

Per diem fee: An arbitrator’s daily rate for hearings. It also is applied for cancellations and postponements during an arbitrator’s cancellation notice periods.

Prima facie case: A case in which evidence presented by one party will be sufficient for that party to prevail if not contradicted by rebutting evidence.

Public policy consideration: The application of certain objectives relating to health, morals, and integrity of government that external law seeks to advance. Such considerations may be raised during an arbitration hearing or serve as the basis for court review once an arbitration award is rendered.


Rebuttal: The phase of a hearing that follows presentation of each side’s principal case in which a party calls a witness to rebut testimony and evidence that the other side entered earlier during its case-in-chief.

Relevant evidence: Evidence that tends to prove or disprove facts in a case.

Remedy: The action or procedure that is followed in order to enforce a right (such a seniority) or to obtain damages for injury to a right.

Rules of evidence: A set of rules governing what evidence should be admitted during a proceeding, typically designed to prevent unreliable evidence from being considered. While state and federal courts prescribe firm rules to govern the offer and acceptance of evidence, these rules are much more relaxed in labor arbitration.


Sequestration: The exclusion from a hearing of witnesses who will be testifying. Individuals who are not excluded from the hearing – even if they will later be testifying –  include the parties’ representatives and individual grievants.

Seniority system: A system that grants employees employment preferences according to the employees’ length of service.

Settled Record: A concept used in discipline cases to limit the introduction of evidence or to avoid re-trying a case that previously was resolved, either by an earlier arbitration decision or by past abandonment of the claim. The record is deemed settled because the opportunity to challenge the discipline was available and now has passed, and the record is complete for future reliance by the parties. A settled record typically is used to demonstrate the progressive disciplinary steps that were taken in the past or to show an employee’s prior notice that the violation of a rule or policy would lead to discipline.

Shop steward:  The Shop Steward (or union representative or union steward) in a unionized workplace is a member of the union whose job it is to represent and defend the interests of the other bargaining unit employees in various discussions with management, including but not limited to, the processing of grievances. His or her function is to act as a liaison between the employees and management, to serve as a sounding board for union member concerns or complaints, and to take part in grievance handling. In order to anticipate employee grievances and avoid labor/management conflict where possible, shop stewards are generally well versed in the terms and provisions of the collective bargaining agreement and are likely to discuss with management any breaches of that agreement. The Shop Steward also serves as a conduit for information, memos, and policy statements by the union. As a rule the Shop Steward is an employee of the company but enjoys certain rights in the execution of his/her union duties. For example, the agreement may provide a certain number of hours per week during which the Shop Steward may engage in union-related business while still receiving pay from the employer. It is often up to the Shop Steward to advise employees when they should file a grievance and assist them in doing so.  An equally important function is to screen employee complaints and provide guidance for employees who may feel they have been aggrieved. This function aims at maintaining a smooth working relationship between management and employees and avoiding frivolous grievances.

Stare decisis: The principle that prior arbitration decisions should serve as a guide or precedent and control the determination of the arbitrator’s decision in the case at hand.

Submission agreement: Used by parties who wish to present a dispute to an arbitrator in the absence of a collective bargaining procedure or other employment agreement that authorizes arbitration. The submission usually identifies the nature of the dispute, the source of the arbitrator’s authority, the issue and relief to be decided, and the relief available.

Subpoena: A document formally requesting the attendance of a witness at a hearing.

Subpoena duces tecum: A document formally requesting the production of documents or other records at a hearing.

Summary judgment: After a party believes it has established that there is no material question of fact in the case before the arbitrator, that party may ask for summary judgment by the arbitrator without proceeding further in hearing or consideration of the case. The arbitrator need not necessarily grant the asking party’s request.


Terms and conditions of employment: Employees generally have the right to join together to address concerns at work and to seek to improve their terms and conditions of work.  Some examples of subjects found to be included in the phrase “terms and conditions,” include rates of pay, wages, hours, fringe benefits, safety, workload, staffing, layoff procedure, and a grievance procedure.  It may be an unfair labor practice for an employer or a union to refuse to bargain on a topic deemed to be a “mandatory subject of bargaining.”  Although no statute expressly defines all the “terms and conditions” of employment, if bargaining over the subject would resolve a significant aspect of the employer-employee relationship, it is more likely to be considered a mandatory subject of bargaining.


Unfair labor practice:  violation of a national or state labor law by management or a union. Principal examples include interference with organizing, discrimination against an individual for union activity, and bad faith bargaining.


Voir dire: A method of examining an expert witness (or a juror) as to his or her qualifications for testifying.


Zipper clause: A provision in a labor agreement, sometimes also known as an integration clause, which states that the agreement is a full and complete understanding of the parties upon completion of negotiations.