By Catherine Ngo Content writer, presenter and podcaster

Chances are you’ve heard of ‘balance of probabilities’ thrown around when it comes to workplace investigations. But what does it mean? 

In workplace investigations, the "balance of probabilities" finding relies on evidence that suggests a higher likelihood of an event occurring. This adheres to the civil standard of proof, which requires the evidence to demonstrate that the alleged behaviour took place with more probability than not.

While the Briginshaw principle should be considered, it does not establish a separate standard of proof. Instead, it serves as a standard of satisfaction, ensuring that specific requirements are fulfilled within the existing legal framework.

The Briginshaw Principle: Evaluating Evidence in Workplace Investigations

In 1938, the High Court of Australia issued a groundbreaking decision in the case of Briginshaw v Briginshaw (1938) 60 CLR 336, which has had a profound and enduring impact on how evidence is assessed and weighed in Australia, including in the context of workplace investigations.

The Briginshaw case involved divorce proceedings, where the husband, Mr. Briginshaw, accused his wife, Mrs. Briginshaw, of adultery. Mr Briginshaw presented evidence that Mrs Briginshaw had received a lift home and a kiss from another man after attending a dance.

The presiding judge dismissed Mr Briginshaw's allegations of adultery, finding that the evidence provided did not meet the required standard of proof. Dissatisfied with this decision, Mr. Briginshaw appealed, arguing that the judge had set too high a standard of proof and that an "inference" of adultery could be drawn from Mrs. Briginshaw's actions.

The High Court considered the appeal and upheld the original decision. However, in reaching this outcome, the High Court emphasised the importance of carefully evaluating the strength of evidence required to prove serious allegations. While the standard of proof in civil cases remains on the balance of probabilities, the High Court ruled that the strength of evidence required varies based on the gravity of the allegations.

In writing the decision for the High Court, Justice Dixon outlined three factors to consider when assessing serious allegations: the seriousness of the allegation, the inherent unlikelihood of an occurrence of a certain description, and the gravity of the consequences resulting from a specific finding.

The Briginshaw Principle has significantly impacted how evidence is evaluated in workplace investigations. It establishes the principle that the seriousness of an allegation should be considered when determining the strength of evidence required to prove it. By applying this principle, investigators can ensure that serious allegations are thoroughly examined and that decisions are based on sound evidence and reasoning.

Clarifying Misconceptions Surrounding the Briginshaw Principle

Contrary to popular belief, the Briginshaw Principle is not a 'standard of proof'. While administrative decision-makers, mainly those responsible for making important findings in workplace investigations, are not legally obligated to apply the Briginshaw Principle, it would be negligent of them not to consider it when determining the facts of a case.

Understanding and Applying the Briginshaw Principle in Workplace Investigations

In workplace investigations, the gravity of the suspected misconduct significantly influences the strength of evidence necessary to substantiate the allegations and reach factual conclusions. This principle, commonly known as the Briginshaw Principle, underscores the need for a more rigorous evidentiary standard for serious allegations.

The Briginshaw Principle should guide all workplace investigations, demanding more compelling and convincing evidence for claims of greater severity. Recognising and adhering to this principle is crucial for investigators to make fair, reliable, and accurate decisions supported by evidence that can withstand judicial or quasi-judicial scrutiny.

Balancing Probabilities vs. Beyond Reasonable Doubt

A significantly higher standard of proof is required in criminal proceedings, known as "beyond reasonable doubt." This means the defence must only convince the court that a reasonable doubt exists. For instance, in O.J. Simpson's murder trial, the glove not fitting his hand created sufficient doubt for him to be found not guilty.

In simpler terms, a finding based on the "balance of probabilities" suggests that something is more likely to have occurred than not. In workplace investigations, an investigator can decide based on conflicting testimonies, such as "he said" versus "she said," by giving more weight to one person's account over another's.

The Role of a Workplace Investigator in Evaluating Evidence in Investigations

The seriousness of an allegation should dictate the level of scrutiny and consideration given by the decision-maker. Serious allegations with significant consequences demand more compelling evidence to establish a firm belief and reasonable satisfaction that the facts in dispute are highly probable.

Despite understanding the legal concept of the balance of probabilities, many internal investigators encounter challenges in its practical application. Decision-makers often hesitate to substantiate allegations unless the evidence meets a standard closer to "beyond reasonable doubt," a threshold higher than the required balance of probabilities.

Where to next?

Organisations should prioritise establishing robust complaints and grievance-handling processes to address inappropriate workplace behaviours effectively. 

This involves upskilling HR professionals and internal WHS teams to conduct internal investigations. A thorough review of internal policies, procedures, and processes is necessary to ensure they align with best practices and provide a fair and transparent framework for addressing employee concerns.

More info: Briginshaw v Briginshaw [1938] HCA 34 – 60CLR 336