Practice Direction #41 – Leading Cases

1.0 This Practice Direction explains

What a leading case is
Why a leading case approach may be adopted
How a leading case is selected
What happens to other cases involving similar issues
How a leading case is processed

2.0 What a Leading Case Is

2.1 A leading case is a case selected from a group of appeals or applications that raise the same novel or significant issue. It generally is assigned early to a Panel that provides case management direction and ultimately decides the appeal or application.

2.2 A leading case is selected with the expectation that the resulting decision may assist the WSIAT in addressing similar issues in related cases. While each case is decided on its own merits, a leading case may help promote consistency and fairness in decision-making.

2.3 A leading case approach is used where it is appropriate to support consistency, fairness, and efficiency in deciding multiple cases involving the same novel or significant issue. It is not intended to replace the WSIAT’s usual development of case law or to limit the individualized adjudication of each case.

3.0 Why a Leading Case Approach May Be Adopted

3.1 The WSIAT may adopt a leading case approach when there are multiple appeals or applications about the same novel or significant issue. This approach allows the WSIAT to prioritize one case for early adjudication, with the aim of providing guidance that may assist in resolving other related cases.

3.2 For the purposes of this Practice Direction, references to a ‘group,’ ‘multiple,’ or ‘related’ cases refer only to appeals or applications that raise the same novel or significant issue. The cases do not need to share the same factual background, workplace, industry, diagnosis, or type of claim.

3.3 The decision to adopt a leading case approach is at the sole discretion of the Chair. In deciding whether to adopt this approach, the Chair may consider whether the case

raises an important issue with implications for other workers or employers, or for the workplace safety and insurance system as a whole;
requires interpretation of new or amended sections of the Workplace Safety and Insurance Act, 1997;
involves the interpretation of a new or amended Workplace Safety and Insurance Board (WSIB) policy;
raises issues in relation to the Canadian Charter of Rights and Freedoms or the Ontario Human Rights Code;
arises, or is likely to arise, in multiple other appeals or applications; or,
involves any other factor that supports adopting a leading case approach.

3.4 A request to consider adopting a leading case approach may come from WSIAT staff, a Vice-Chair or Panel member, or one of the parties. If a party is making the request, it must be in writing and provided as early as possible. The request should explain why the leading case approach should be adopted for a particular issue.

4.0 How a Leading Case Is Chosen

4.1 Once a leading case approach is adopted, the Chair will determine which case will be chosen as the leading case. In making this decision, the Chair considers factors such as

the procedural stage of the appeal;
the completeness or quality of the evidentiary record;
whether the case is reasonably representative of other related cases;
whether the case raises the main issue(s) to be addressed in the leading case and can be adjudicated efficiently without additional issues causing unnecessary delay;
whether both worker and employer perspectives are represented;
whether the parties are represented;
the positions of the parties on whether the case should be selected as the leading case; and,
whether the case is suitable for an early hearing date.

4.2 Before selecting a case as the leading case, the WSIAT will normally invite the parties to provide submissions on its suitability for selection, including whether they agree to their case being selected. Where circumstances require, the Chair may proceed without inviting submissions.

4.3 A request to have a case selected as the leading case may come from WSIAT staff, a Vice-Chair or Panel member, or one of the parties. If a party is making the request, it must be in writing and provided as early as possible. The request should explain why the case is appropriate to be the leading case, referring to the factors in section 4.1.

5.0 What Happens to Other Cases Involving Similar Issues

5.1 When a leading case is chosen, other cases raising the same or similar issues may be placed on hold. Sometimes the WSIAT will make it optional to have a case placed on hold – the parties in those cases will be notified. Other times the WSIAT will identify that a case needs to be placed on hold. If a party objects to their case being placed on hold, the WSIAT will consider the objection. Cases placed on hold may be made inactive.

5.2 Where appropriate, the WSIAT may allow preliminary or unrelated issues to proceed in an appeal or application that has been placed on hold. This may include bifurcation of issues (a process where one issue is heard and decided before another) or partial progression of the case where doing so will not undermine the purpose of the leading case approach.

5.3 Cases placed on hold will be reviewed periodically to determine whether the hold remains appropriate. Parties whose cases are on hold will be provided with general updates on the progress of the leading case, as appropriate.

5.4 A general description of the selected leading case may be posted on the WSIAT’s public website. No personal, confidential, or identifying information about the parties in the leading case will be included.

5.5 Once the leading case is decided, the WSIAT will review all related cases that were placed on hold and provide the leading case decision to the parties in those cases. The WSIAT will notify the parties of next steps as soon as possible. Parties may make submissions about how the leading case applies to the facts of their own case.

5.6 Decision-makers in other cases aren’t required to follow the decision in a leading case. The WSIAT decides each case based on the merits and justice of each case. However, the reasoning in a leading case may be persuasive when the facts or issues are similar.^[1]

6.0 How a Leading Case Is Processed

6.1 A leading case generally follows the same processing steps as other cases. A Panel is usually assigned before the hearing to provide direction on preliminary issues and/or the hearing process. Once assigned, the Panel is responsible for managing all procedural aspects of the case and for deciding the case.

6.2 The Chair may appoint a 3- or 5-member Panel. A 3-member Panel includes a Vice-Chair or the Chair, one worker member, and one employer member. A 5-member Panel includes a Vice-Chair or the Chair, two other Vice-Chairs, one worker member, and one employer member. The composition of the Panel may change during the processing of the leading case – this could be in response to procedural rulings, changes to the issues, or bifurcation of issues. The parties will be notified of any change to the Panel.

6.3 Notice of a leading case may be provided to the WSIB where the WSIAT determines that its participation would be helpful. Intervenors may also be invited to participate in a leading case.

6.4 The WSIB and intervenors will have limited participation in the hearing process. The Panel will determine the extent of their participation and access to materials, after considering the submissions of the parties.

6.5 Tribunal Counsel may assist in processing a leading case.

7.0 References and Resources

7.1 Legislative Authority

Workplace Safety and Insurance Act, 1997, section 131 (the WSIAT can determine its own practice and procedure); section 124(1) (Decisions based on merits and justice; the WSIAT not bound by precedent); and, section 174 (who may hear and decide appeals at the WSIAT)

7.2 Decisions

The following decisions illustrate how the WSIAT has dealt with issues related to leading cases, intervenors, and notice

WSIAT Decision Nos. 1169/20I and 1169/20I2 (participation of intervenors and WSIB as amicus curiae)
WSIAT Decision No. 95/09I (the WSIAT’s approach to a leading case)
WSIAT Decision 2346/12I3 (application for intervenor status)

7.3 Related Practice Directions

Effective date August 26, 2026