Terms We Use

The Act

The Workplace Safety and Insurance Act, 1997.


After we make a Case Record for an appeal, any new documents added to the record are put together in a booklet called an addendum.


An adjournment means that the hearing can’t proceed or be completed on its scheduled day. It will be rescheduled for another day.


Adjudication is the process where a Vice-Chair or Panel hears and decides a case.


An adjudicator is a person who decides a case. At the WSIAT, a case is usually decided by 1 adjudicator (a Vice-Chair). Sometimes it is decided by 3 adjudicators (a Vice-Chair, a Worker Member and an Employer Member). In exceptional circumstances, it is decided by 5 adjudicators (3 Vice-Chairs, a Worker Member and an Employer Member).


An affidavit is a written statement regarding a statement of facts that is supported by the affirmation of the person making the statement.


An affirmation is a solemn declaration by the person making the statement.


ADR means Alternative Dispute Resolution. ADR is a way of resolving a single-party appeal without a full hearing.


An appeal is when a party challenges a WSIB decision.


An appellant is the person who starts an appeal at the WSIAT.

Business Days

A business day is a weekday (Monday, Tuesday, Wednesday, Thursday, Friday) that is not a holiday.

Case Materials

The case materials for an appeal at the WSIAT can include the Case Record, Addenda, the Hearing Ready Letter and Post-Hearing Addenda. These documents will be used to decide your appeal.

Case Record

A Case Record is a booklet prepared by us that contains the Workplace Safety and Insurance Board file at issue and any related claim files.


A claim is a request for benefits at the Workplace Safety and Insurance Board.

Closing Statement

A closing statement summarizes the main points you have made during the hearing. It’s given at the end of the hearing.


Consent is your agreement. For example, we ask workers if they agree to the release of their information in the case materials to the employer.


At the end of a hearing, the person deciding the appeal writes a decision. It tells everyone involved in the appeal whether the appeal is allowed or denied. It also gives the reasons why the appeal was allowed or denied.


Disclosure is the process of sharing evidence or information with the other participating parties and the WSIAT.

Disclosure Period

The disclosure period is the time before a hearing when parties must share evidence or information with the other participating parties and the WSIAT.

Downside Risk

A downside risk means that there is a reasonable chance that an appellant (worker or employer) may be worse off than if they had not appealed. For example, the appeal may result in lower benefits for a worker or higher claim costs for an employer.


E-File is WSIAT’s service that allows parties to send us information electronically.


E-Share is WSIAT’s service that allow us to send information electronically to the parties.


EIP means our Early Intervention Program. We use ADR and mediation in the EIP to resolve appeals without an oral hearing.

Entitlement to Benefits

Some workers who have suffered a work-related injury or disability may receive money or health care treatment from the Workplace Safety and Insurance Board. If they get this money or treatment it is called "entitlement to benefits".


Evidence is information that proves or disproves a fact. Evidence can take many forms including testimony, medical reports or written statements.


A hearing is a meeting where the adjudicators consider the submissions of the parties. Some hearings are held by videoconference, in person, or by teleconference where arguments are heard and questions are answered. Some hearings are held in writing, where arguments are made by written submissions.


An inactive appeal is an appeal that is not ready for hearing. We won’t move the appeal forward until we get the information we need from the parties.

Interested Party

An interested party is a person or organization that may be affected by the outcome of the appeal. The WSIAT decides who has an interest in the appeal.


An intervenor is an individual or group we may invite to participate in an appeal. They aren’t a party to the appeal. Their role is limited.

Issues on Appeal

The issues the parties challenge are called the issues on appeal.


Jurisdiction is the authority the WSIAT has to decide the issues on appeal.


Mediation is a way of resolving a 2-party appeal without a full hearing.

Medical Assessor

Medical Assessors are health professionals who assist the WSIAT by providing opinions in individual cases. They respond to specific requests made by a Vice-Chair or Panel in an appeal.

Medical Counsellors

Medical Counsellors are a group of highly qualified medical specialists. They are consultants to the WSIAT. They’re required to be impartial.

Medical Discussion Papers

Medical Discussion Papers provide a balanced broad and general overview of a medical topic. They are based on the medical knowledge available at the time they are written. They are not peer reviewed.


MLO means the WSIAT’s Medial Liaison Office. The MLO provides assistance on medical issues.


Notice means telling someone about something. For example, by giving someone “notice of appeal”, you’re letting them know that you’re starting an appeal at the WSIAT.


An Order-in-Council (OIC) is an order made by the Government of Ontario. Each Vice-Chair and Member of the WSIAT is named to their position through an Order-in-Council appointment. Vice-Chairs and Members are sometimes also called “OICs”.


OEA means the Office of the Employer Adviser. They help smaller employers with workplace safety and insurance claims and appeals.


OWA means the Office of the Worker Adviser. They help workers who are not members of unions with workplace safety and insurance claims and appeals.


OVCR means the WSIAT’s Office of the Vice-Chair Registrar. Staff in the OVCR are the main point of contact for parties. They process appeals and applications.

Opening Statement

An opening statement is an introduction of your case. It explains what you are appealing, why, and the outcome you want. It’s given at the start of the hearing.

Outstanding Issues

Outstanding issues are those that have not concluded at the WSIB.


A party is a worker or an employer who is involved in an appeal. Usually, only people who may be affected by how the appeal is decided can participate. The WSIAT can still decide the appeal if a party decides not to participate.


A panel is the people who will decide an appeal. A Vice-Chair, a Worker Member and an Employer Member, decide some appeals. Together, these 3 people are called a panel.


Policy is the written rules the WSIB uses to interpret and apply the Act to individual cases.


Post-hearing work happens in some cases when a Vice-Chair or Panel doesn’t have enough information to make a decision after a hearing. They may need more evidence or submissions from the parties.

Practice Direction

The WSIAT’s Practice Directions set out the practices and procedures for WSIAT appeal and applications.

Preliminary Issues

Preliminary issues are matters that need to be addressed before the hearing can proceed.


A reconsideration is when the WSIAT reviews its decision. If significant new information might change the decision, or if you feel the Vice-Chair or Panel did not consider important evidence or made a mistake in law or process, you can ask for a reconsideration.


A representative is the person who helps a worker or employer with an appeal. A representative deals with the WSIAT for you and presents your case at the hearing. You must authorize someone to represent you.


A respondent is the person who replies to an appeal at the WSIAT. For example, when a worker starts an appeal, the employer is usually the respondent.


Seized means the Vice-Chair or Panel who is assigned to an appeal will continue to hear the appeal or application until it’s decided.

Side Member

A side member is a person from the WSIAT who helps to decide appeals. There are side members for both workers and employers. In some appeals they work with Vice-Chairs at hearings to talk to parties and help write the decision. The Government of Ontario appoints side members to the WSIAT.


Submissions are oral or written statements on law, policy or facts about a case, made in person or in writing to an adjudicator.


A summons is a document that requires a person to attend a hearing to give evidence or bring documents on a certain date.


Testimony is the oral statement of a witness at a hearing after giving an affirmation to tell the truth.

Time Extension

A time extension is a request for more time to complete an action. For example, if you miss your time limit to appeal, you can apply for an extension of time to appeal.


A transcript is a written record of an oral hearing made by a professional.


TCO is the WSIAT’s Tribunal Counsel Office. TCO provides legal assistance in WSIAT appeals and applications, particularly in cases with complex or novel issues. TCO also acts as legal advisers for the WSIAT.


A Vice-Chair is the person from the WSIAT who will hear your appeal and write the decision. For some appeals, a Vice-Chair works with a Worker Member and Employer Member, as a Panel, to hear and decide the case. The Government of Ontario appoints Vice-Chairs to the WSIAT.

The Vice-Chair Registrar

The Vice-Chair Registrar is a Vice-Chair. They adjudicate appeals. They also give direction and guidance in appeals and pre-hearing processes.

Will Say Statement

A “will say” statement is a summary of the evidence a witness will give at the hearing through their testimony.


The WSIA is the Workplace Safety and Insurance Act, 1997. The law of the province of Ontario after 1997 that provides benefits and services to eligible workers after a work-related injury.


The WSIB is the Workplace Safety and Insurance Board. It is a public organization, created by the Government of Ontario that decides who is entitled to benefits and services under the law. The WSIB also provides these benefits and services.


The WSIAT is the Workplace Safety and Insurance Appeals Tribunal. We are a public organization created by the Government of Ontario. We are the final level of appeal in the workplace safety and insurance system. We are separate from and independent of the WSIB.