Why every workplace investigator should be a case law expert and other lessons from a recent arbitration decision

As workplace investigators, we always think about the possibility of our work being legally scrutinized: either before a court, tribunal, or arbitrator. While we know that some cases carry greater risks than others, we know that the possibility of a legal challenge exists in every case.

A significant portion of my practice is to review and “stress test” the investigative work of other investigators. This means that I think a lot about potential weaknesses in an investigation, and how these can be mitigated or addressed, either in the investigation report or otherwise (for example, I may recommend that additional investigative steps be taken to rectify a deficiency). I also think about the form of the investigation report – ensuring that it “looks” professional and is capable of being easily understood by the reader.

That said, even with a rigorous review process in place, it can be difficult to predict what issues a legal decision maker may have with an investigation. Part of this unpredictability may stem from the fact that legal decision makers operate in a different environment than workplace investigators. What I mean by this is that, practically, there are typical constraints that apply to workplace investigations that may not exist in legal proceedings. For example, workplace investigators are usually under significant time pressure to collect evidence, they generally do not have legal powers to compel individuals to participate or produce documents, and, importantly, they must be mindful of confidentiality when deciding what evidence to obtain (the idea being that if too many witnesses are involved, it is likely to have a detrimental impact on the reputation of the parties and the workplace).

One way to guard against legal scrutiny is to be familiar with case law that addresses investigation flaws. These cases usually stem from employment or human rights matters. While the facts of these cases vary significantly from one to the next, there is a discernible pattern of flaws that emerges. I encourage all investigators to become familiar with the relevant case law – and to perhaps approach the investigation work being reviewed in these cases from a place of learning, rather than judgment; we are all vulnerable to getting our work legally reviewed and can all learn from one another.

A recent arbitration case¹ provides some reminders about things we can do to avoid legal scrutiny of our investigative work:

• • Verify or attempt to verify the evidence of the parties where possible. While there may be good reason not to obtain relevant evidence, this must be explained in the report. In the arbitration case cited above, it was noted that only the two parties and one witness had been interviewed once, and that none of their statements were verified by obtaining other evidence. According to the arbitrator, the concern about this was heightened by the fact that the complainant had a poor recollection of some of the alleged events.
  • Avoid using “credibility words” without providing thorough reasons to support the use of these words to assess credibility. I addressed this in a past blog about credibility assessments. In the case at hand, the arbitrator noted that the investigator concluded that all five allegations were substantiated, at least in part because the alleged events were plausible. The arbitrator remarked that thorough reasons were not provided about why the events were plausible. Contributing to the arbitrator’s concerns, was the fact that the respondent had been asked very few questions about one of the allegations and that some evidence that undermined the investigator’s assessment appeared to have been discounted.
  • Refrain from formulating and recording in the file subjective assessments about the parties and their credibility before getting to the report writing stage. Also, limit any such assessments to what is relevant to assess credibility and make findings. The arbitrator in the case cited above was concerned about bias because the investigator had written down some of their observations about the respondent in their notes. For example, the investigator had noted, “Credibility: Likely did it all,” “So much smugness,” and “This is a frat boy.”
  • Avoid relying on the respondent having engaged in one type of behaviour, to support that they engaged in a different alleged behaviour. In the case at hand, for example, the investigator had indicated in the notes that if the respondent made one comment, then he “more likely than not” made another alleged comment (which was of a different nature than the other comment). The arbitrator disagreed with this reasoning.

All of these points serve as a good reminder to investigators (and in-house investigation departments) to review their practices to assess whether there is anything they could do to mitigate the risk of their investigations being legally scrutinized. Process reviews, investigation training, and education go a long way to identifying and resolving potentially problematic aspects of our work.

¹Air Canada v. Canadian Union of Public Employees, Air Canada Component, 2025 CanLII 39078 (CA LA).

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