Conducting a Workplace Investigation in Ontario: The Basics for Employers

Once an Ontario employer knows it needs to investigate a workplace complaint, the next question is usually: how, exactly? There's no single mandated script, but a defensible investigation tends to follow a similar shape regardless of the industry or the size of the business.

Here's the process broken into its basic steps.

Step 1: Decide Who Will Investigate

Before anything else, figure out who is going to run the investigation.

• Internal investigator (HR, a manager, an owner) — often workable for less serious, lower-conflict matters.
• External investigator — generally the better choice where a senior person is implicated, where there's a real or perceived conflict of interest, or where the allegations are serious.

The wrong choice at this stage can undermine the whole process — an investigator who reports to the accused, or who is close to one of the parties, creates a fairness problem before a single interview happens.

Step 2: Plan the Scope Before You Start

A rushed investigation that skips planning tends to miss things. Before interviewing anyone, work out:

• Exactly what allegations are being investigated (write them down precisely)
• Who needs to be interviewed — the complainant, the respondent, and any witnesses
• What documents or records might be relevant (emails, schedules, prior complaints)
• A realistic timeline, given that unreasonable delay is itself a problem

Step 3: Interview the Parties and Witnesses

Interviews are the core of most workplace investigations. A few practical principles apply across the board:

1. Interview the complainant first, in enough detail to understand exactly what's alleged.
2. Tell the respondent what they're accused of in enough detail to respond meaningfully — procedural fairness generally requires this, even though it can feel uncomfortable.
3. Interview witnesses separately, without other parties present, and avoid leading questions.
4. Take contemporaneous notes or a recording (with appropriate notice), since memory fades and credibility findings often turn on documented detail.
5. Stay neutral. An investigator who has already decided the outcome before finishing the interviews undermines the process.

Step 4: Weigh the Evidence

After the interviews, the investigator has to make findings — which is often the hardest part, especially where accounts conflict directly.

• Assess credibility based on consistency, corroboration, and plausibility, not just who seems more senior or more persuasive in the room.
• Apply a balance of probabilities standard — whether it's more likely than not that the alleged conduct occurred — rather than a criminal "beyond a reasonable doubt" standard.
• Be honest where the evidence is inconclusive. "Unable to substantiate" is a legitimate finding; it doesn't have to be an all-or-nothing verdict.

Step 5: Report, Decide, and Follow Up

Closing the file with a report and a decision — not just letting the matter quietly fade — is what turns an investigation into something that will hold up if it's ever reviewed later.

Common Mistakes to Avoid

• Starting interviews before deciding the precise scope of the allegations
• Letting an obviously conflicted person run the investigation
• Failing to give the respondent a real chance to respond
• Promising an outcome or a level of confidentiality the investigator can't actually deliver
• Treating the written report as optional once a decision has been made informally

Frequently asked questions