Workplace investigations are an integral part of maintaining a safe and healthy work environment for employees. To ensure that investigations are conducted fairly and accurately, relevant and reliable evidence is an essential requirement. The use of unreliable evidence can not only result in incorrect findings but also potentially damage an organisation’s reputation and expose it to legal liabilities.

In this context, it is crucial for employers to prioritize the collection and preservation of reliable evidence that is credible and trustworthy. Having an understanding of what makes certain evidence more reliable or relevant than others is hugely beneficial as it allows the investigator to differentiate between what they should and shouldn’t utilise to make important investigative decisions. This article will explore the idea of reliability and relevance when it comes to investigative evidence and offer advice for examining evidence in relation to these concepts.

What is relevant and reliable evidence?

For all evidence, relevancy and reliability are two of the most important factors in deciding whether the article can be used to help draw an accurate picture of what occurred and how to proceed. Without these two attributes, a piece of evidence is not likely to be consistent, probable or believable and should not be used to make decisions regarding the investigation.

Relevancy refers to the connection between the evidence and the investigation at hand, and it plays an important role in identifying evidence that can be used to make lawful workplace decisions. For it to be relevant, a piece of evidence should be connected in a legitimate manner to the circumstances that are being examined. No matter the form it takes on, it needs to be directly related to the case and have an impact on the facts of the issue.

Keep in mind, however, that this doesn’t mean that evidence that is not directly related is not useful- an investigator may still use additional evidence to understand a case, assess it and draw conclusions. Furthermore, some pieces of evidence may not be considered appropriate when examined independently, but gain relevancy when looked at in conjunction with other types of reliable evidence. 

The evidence used in an investigation also has to be reliable, which essentially means that it needs to be a dependable source that is trustworthy and credible. This does not necessarily mean that it has to be purely objective – it is inevitable that when you’re working with witness testimonies and anecdotal accounts of events, there is a certain level of bias present. As an investigator, however, you must understand how to account for both conscious and unconscious bias and recognise when and where it is impacting the reliability of the source.

For example, if one employee’s account of a situation contradicts all the other accounts you’ve heard or is accusatory and/or self-serving, you may have to treat the testimony with some scrutiny. This doesn’t mean, however, that you should make decisions based on assumptions about a witness’s behaviour or discount their take just because they had a different perspective – it simply means that investigators must be critically aware of the evidence they use and utilise several different types to ensure they don’t reach biased conclusions.

Below are some tips for investigators to help them with the process of identifying reliable evidence that can be used to make unbiased investigative decisions.

Tips to ensure you utilise reliable evidence

1. Corroboration of Evidence

Evidence corroboration is where a testimony, account or analysis of the case can be backed up by not one or two, but a collection of evidence that all supports the same conclusion. The collection of evidence should ideally include a range of different types, such as witness testimonies, videos/photos, emails, text messages and written reports. During the investigation, it’s crucial for any decisions or verdicts you make to be backed by evidence that can be corroborated. If four out of five key pieces of evidence point to one theory, then it has a greater likelihood of being the truth as opposed to what the remaining piece of evidence implies.

reliable evidence

2. Consistency

The complainant’s or defendant’s account of what occurred should be consistent with the evidence that emerges from the investigation. The reliability of their testimony can be brought into question if inconsistencies or contradictions arise in their version of events vs what the evidence suggests. Whilst there isn’t one single factor that can determine if someone is telling the truth, keeping an eye out for consistency will help you decide how much you want to rely on a particular piece of evidence.

Note that having thorough and accurate interview documentation is very important for this purpose. In fact, popular theories about how to ‘spot’ a lie based on body language and behaviour have been conclusively proven to be false – thorough documentation and careful fact-checking against other evidence is the only reliable way to identify a lie or deception.

3. Statement Plausibility

Assessing the plausibility of evidence, in particular witness testimonies, helps investigators employ deductive reasoning and logic to infer what happened. Investigators have to take into account what they know as facts and all the acquired evidence when deciding how plausible a certain chain of events is. When doing so, it’s also important not to discount the possibility of collusion between employees, evidence tampering and anomalies in the investigative process. If you feel that a particular take on the investigation is not plausible with the evidence present, it may be time to ask more questions and dig deeper for answers.

4. Expert Input

In some aspects of the investigation, expert input can be a great way to understand certain evidence that you may not have the necessary experience or qualifications to understand. This could include medical reports, forensic data, financial reports etc. In these circumstances, an unbiased third-party professional who has specialist knowledge can be called upon to lend their expertise.

The experts can include individuals such as engineers, psychiatrists, accountants, forensic scientists and security experts who are able to assess relevant evidence with their knowledge and experience. Their opinion or judgement can also be corroborated by another expert(s) to ensure you’re working with reliable evidence. Expert input can not only have a huge difference in the final outcome but also improve the credibility of the investigation as a whole.

Ensuring that the evidence utilised in workplace investigations is relevant and reliable is essential in making informed decisions at the conclusion of an investigation. Trustworthy and credible sources of information allow investigators to remain as objective as possible and also provide legal protection for the organisation. Ultimately, the use of reliable evidence is crucial for promoting transparency, accountability, and fairness in workplace investigations.