A Closed Mind: Witness Selection, Credibility, and the Weighing of Evidence

Workplace Investigations Under the Microscope Part 2 of 3

Procedural fairness in workplace investigations is facing increasing scrutiny
and is a defining factor in whether an investigation will be upheld. This three part series looks at the lessons emerging for employers, HR leaders, investigators, and legal counsel from a recent arbitration decision.

In Part 1, we looked at how a series of communications between the investigator and the employer created a reasonable apprehension of bias and cost an otherwise qualified investigation its independence. But independence is only the starting point. An investigator can remain at arm’s length from the organization and still fall short by approaching the evidence itself with a closed mind or evaluating it unevenly. The second article in this three-part series turns to how that risk surfaced in the grievance review panel’s decision1 in the investigator’s choices about which witnesses to interview, the assessment of credibility, and the weighing of the evidence.

The grievance arose from an investigation into serious allegations of harassment, discrimination, and systemic discrimination. The union alleged that the employer failed to meet its duty to investigate. The panel agreed. I examine some of the panel’s reasons below.

The panel was careful to acknowledge that an investigation need not be perfect to be fair. Investigators are not required to interview every possible witness, run down every piece of information, or resolve every inconsistency. What fairness does require is balance: an open mind and a genuine pursuit and testing of all essential evidence. The absence of that balance ultimately undermined this investigation.

A fair investigation is not a perfect investigation

An investigator has some latitude in deciding how to conduct an investigation, including who to interview and how far to pursue a line of inquiry. Provided it still meets a baseline of procedural fairness, a process will not be found unreasonable simply because, with hindsight, it could have been done differently or more thoroughly.

But that latitude is not unlimited. An investigator cannot overlook crucial evidence and cannot approach the exercise in a way that favours one party over the other. When an investigation is under scrutiny, the question is not necessarily whether the investigator reached the right conclusion. As the panel put it, they were looking closely for impartiality and fairness.

The focus is on whether the investigator took reasonable steps to gather relevant evidence based on the information available at the time, and whether their decisions not to pursue additional evidence were justified.

Overlooking a key witness

One of the panel’s primary concerns arose from the investigator’s decision not to interview a witness the complainant had identified from the outset as important. The witness was closely connected to the heart of the complaint – among other things, a co-subject of one of the rumours at issue and someone with direct knowledge of the complainant’s experience. Yet the investigator decided not to interview them.

The issue was not that a witness put forward by a party was not interviewed. It was about how the investigator arrived at that decision in the circumstances. The panel faulted the investigator for assessing the witness’s potential value by reference to only the complainant’s reply to the respondents’ evidence summaries, rather than against the full scope of the complaint and the entirety of the complainant’s evidence. That fuller evidence demonstrated that the witness likely had relevant information to share.

The investigator also documented careful reasons for interviewing the witnesses they chose – several of whom were likely to be adverse to the complainant – but engaged in no comparable analysis for the witnesses the complainant had proposed who were not interviewed. The result was a rigorous justification for the witnesses interviewed compared with little examination of the decision to exclude another.

The decision reinforces that the more squarely a witness connects to the allegations, the harder it becomes to justify a decision to exclude them. If a witness may be able to provide evidence that could affect a finding, it follows that reasonable efforts should be made to interview them.

Test assumptions

A closely related issue was untested assumptions. In declining to interview the witness, the investigator effectively reasoned that because the complainant had not spelled out what the witness would say, the witness must have had little to offer. Yet the investigator reached that conclusion without returning to the complainant to ask them about it, or pursuing an interview with the witness to confirm the relevance of the information they could provide.

Assumptions about what a witness knows, or that are based on what a party left unsaid, can quietly shape the scope of an investigation. When an assumption is doing that kind of work, particularly when a finding turns on it, fairness calls for testing it before acting on it. A brief follow-up question can confirm or dispel the assumption. Leaving it untested can jeopardize the fairness of the entire process.

Give the parties an opportunity to address gaps

Resting findings on assumptions caused another issue. The panel was troubled that the complainant was not given a meaningful opportunity to respond to the investigator’s report. Procedural fairness does not require that parties be afforded an opportunity to debate an investigator’s ultimate findings.2 But the complicating factor in this case was that the complainant was not provided an opportunity to fill in the gaps, address conflicting evidence, or help clarify some of the investigator’s assumptions before the findings were made and the report was issued.

That was further aggravated by the employer relying on the report’s findings as the final word to dismiss the complainant’s complaint.

An investigation that reaches firm conclusions without giving the affected parties a chance to address gaps or contradictions in evidence is vulnerable, especially where the stakes are high. Building in an opportunity to respond provides fairness and strengthens the result, surfacing information that might otherwise be missed and reducing the risk that findings are rooted in incomplete evidence or incorrect assumptions.

Credibility and reliability: substance over labels

The panel also considered whether the investigator had improperly blended the concepts of credibility (was the witness being truthful?) and reliability (was the witness’s evidence factually accurate, even if honest?). The panel took a practical view and found that it’s not about the terminology the investigator uses, but the substance: whether the investigator genuinely separated the honest-but-mistaken witness from the untruthful one.

The concern was that the investigator treated a witness’s inaccuracy on one point as supporting a broader finding that the witness was dishonest, including on unrelated matters. It’s common for a witness to be wrong about a detail but truthful from their perspective. An investigator has to keep those ideas distinct and resist letting a single discrepancy taint the assessment of the entirety of the witness’s evidence.

Applying scrutiny evenly

The most serious concern was not any one finding, but a pattern. The panel found the investigator subjected the complainant to intense scrutiny, drawing sweeping adverse credibility findings from minor, and in places nonexistent, inconsistencies. At the same time, the investigator treated the evidence of adverse witnesses more forgivingly and, at times, accepted it without critical examination.

A few examples illustrate the imbalance. The investigator made a pointed credibility finding against the complainant for declining to adopt the investigator’s reading of some emails, while overlooking other evidence that corroborated the complainant’s account. The result was a credibility finding lacking in evidentiary foundation. The investigator accused the complainant of an “artful ordering” of events on an issue of timing, inferring duplicity, but the evidence did not refute the complainant’s interpretation and the investigator never put it to the respondent to clarify. The investigator also omitted from their report a material misrepresentation in a respondent’s evidence that was contradicted by the documentary record and neglected to weigh that contradiction against that respondent’s credibility. There were also examples of relevant evidence left unexamined.

Taken individually, any one of these could perhaps be explained. Taken together, the panel found they revealed “a fundamentally one-sided and unfair approach.” The investigator rejected the complainant’s account even where evidence supported it, and accepted evidence adverse to the complainant’s evidence without applying the same rigour. This asymmetry was illustrative of a closed mind. Even absent intention, it was not simply a matter of errors in judgment or interpretation in assessing the evidence. It was a settled lean that kept the investigator from weighing the evidence on both sides equally.

Good process does not guarantee fair analysis

In the first article, I noted that the panel praised the investigator’s method for gathering evidence and described the investigator’s process for preparing and allowing parties and witnesses to review their statements as fair and thorough. The deficiencies arose in how the investigator assessed and treated the evidence once it was received.

One of the lessons from the decision drives home that fair collection of evidence is only the first step. An investigator can follow a careful, transparent, well-documented process for interviewing witnesses and gathering evidence yet still undermine the investigation by assessing the evidence unevenly. Procedural fairness must carry through to the analysis. Investigators must avoid searching for evidence in a way that favours one conclusion, accepting some evidence at face value, demanding stronger proof from some witnesses than others, and overlooking corroborative evidence.

Key takeaways

As investigators, it’s essential that we continuously challenge our own biases and evaluate our processes to ensure we remain neutral through every step of the investigation. Here are some practical considerations to keep in mind flowing from the panel’s decision:

• Assess proposed witnesses against all the evidence. The decision to include or exclude a witness should rest on the full scope of the allegations and evidence.
• Document witness exclusions as carefully as inclusions. Explain why you chose not to interview a witness. Ensure it does not leave a gap in essential evidence or result in an imbalance between witnesses expected to provide evidence relevant to one party’s account compared with another’s.
• Test assumptions before relying on them. When an assumption about what a witness knows, or what a party left unsaid, is shaping the investigation and a finding, test it by pursuing the information necessary to make an evidence-based finding.
• Give the parties a chance to address gaps and inconsistencies. Provide parties the opportunity to address new or contradictory evidence before credibility assessments and findings are made and the report is issued.
• Keep credibility and reliability distinct. Credibility is honesty; reliability is accuracy. An honest witness can be mistaken, and inaccuracy on one point does not make the entirety of a person’s evidence either inaccurate or dishonest.
• Apply the same scrutiny to everyone. Test a respondent’s account as rigorously as the complainant’s and carefully consider and pursue evidence that seems inconsistent with any emerging “theory,” not just the evidence that supports it.
• Ask what would change your mind. Before finalizing a finding, pause on the contrary evidence. If evidence that could shift your conclusion has not been thoroughly pursued, gather and consider it before findings are made.

A balanced investigation is not one that treats every witness identically or interviews everyone who is put forward by the parties. It’s one that keeps an open mind, recognizes and tests assumptions, and weighs the evidence on all sides with the same diligence and care.

As information is gathered, investigators can be tempted to begin forming conclusions before all the evidence has been received. One of the best pieces of advice I was given early in my career as an investigator was to let the facts guide you. In practice, that means resisting the urge to settle on a conclusion too soon and remaining willing to follow the evidence wherever it leads.

Independence and an open mind are two of the three threads running through this decision. In Part 3, we will look at the lessons the panel’s decision offers on investigating allegations of systemic discrimination – why looking at incidents one at a time can miss the broader context, and what employers and investigators need to do to connect the dots.

Natasha Savoline is a partner, HR advisor, and workplace investigator at Bernardi Human Resource Law LLP. She supports organizations in cultivating healthy workplace cultures through HR/employment law advisory services, training, conflict mediation, leadership coaching, culture assessments, and workplace investigations.

Connect if you would find a conversation helpful.

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1 Governing Council of the University of Toronto v. University of Toronto Faculty Association (June 1, 2026) (Grievance Review Panel) (unreported).

2 Carreau v. Canada (Attorney General), 2025 FC 1537 (CanLII). See my LinkedIn article about Carreau: Leadership inaction can be harassment and parties have no right to comment on final investigation findings.