How a fair, structured workplace investigation typically runs — from receiving a complaint through gathering evidence, applying procedural fairness, making findings and reaching an outcome.
General guidance only. This article explains how a workplace investigation commonly works, in plain language, to help you understand the process. It is not legal advice and does not replace advice tailored to your situation. Where formal legal advice is required, we can work alongside appropriately qualified legal advisors.
Not every concern needs a formal investigation. Many issues are better resolved through a direct conversation, mediation or a management response. An investigation is usually appropriate when there is a specific allegation of serious misconduct, bullying, harassment, discrimination or a policy breach — particularly where the facts are disputed and the outcome could be significant for the people involved.
Before launching an investigation, get clear on what is actually being alleged, whether the conduct (if proven) would breach a policy or expected standard, and whether any immediate steps are needed to keep people safe while the matter is looked into.
A good investigation starts with a plan. Setting clear terms of reference keeps the process focused and fair. The terms of reference typically cover:
Choosing the right investigator matters. They should be impartial, have no conflict of interest, and be capable of handling the matter sensitively. For serious or sensitive allegations, an external investigator is often the safer choice.
Information should be shared on a strict need-to-know basis. Confidentiality protects the integrity of the process and the privacy and wellbeing of everyone involved. At the same time, the welfare of the complainant, the respondent and any witnesses should be actively considered throughout — including access to support and, where appropriate, employee assistance.
Procedural fairness (also called natural justice) is the backbone of a defensible investigation. In practice it means:
Getting procedural fairness right is often what determines whether an outcome holds up if it is later challenged.
The investigator collects relevant evidence and interviews the people who can speak to the allegations — usually the complainant, the respondent and any witnesses. Documents such as emails, messages, rosters, records and CCTV may also be relevant.
Interviews should be conducted fairly and consistently: explain the purpose and confidentiality, ask open questions, let the person tell their account, and test it against other evidence. Keeping accurate notes or records of each interview is essential.
People being interviewed — particularly a respondent — are generally entitled to bring a support person to interviews. A support person is there for support, not to answer on the person’s behalf or to act as an advocate. Making this role clear at the outset avoids confusion during the meeting.
Workplace investigations are not criminal proceedings. Findings are made on the balance of probabilities — that is, whether it is more likely than not that something occurred. The more serious an allegation, the stronger and more careful the evidence needed to support a finding should be.
For each allegation, the investigator weighs the available evidence, assesses credibility where accounts conflict, and reaches a finding: substantiated, not substantiated, or unable to be determined.
The findings are set out in a written report. A clear report typically records the allegations, the process followed, the evidence considered, the analysis for each allegation and the findings reached. It should focus on the facts and the reasoning, and avoid straying into matters outside the terms of reference.
Making findings and deciding the outcome are separate steps. Once findings are made, the business decides what action, if any, follows — which might range from no further action through to training, a change to arrangements, a warning or, in serious cases, disciplinary action. Decisions should be proportionate and consistent with how similar matters have been handled.
If you are facing a complaint and are not sure whether or how to investigate, Robust HR can help you scope the matter and run a fair, defensible process.