From Evidence to Insight: A Guide to Writing Effective Investigation Reports


When it comes to writing an investigation report you may find yourself wondering where to start or how to bring together all of the evidence you have gathered.

Perhaps you have spent a great deal of time carrying out a disciplinary investigation and the thought of writing the crucial investigation report makes you wonder how you are going to squeeze it into your schedule.

Organisations are faced with a wide range of time pressures and writing an investigation report compounds the ever increasing workload of healthcare staff and HR professionals alike.

Our experience as independent investigators means we have developed solid processes for conducting a wide range of investigations including MHPS investigations and workplace investigations, as well as providing a CPD accredited training course on conducting workplace investigations.

In this guide we provide our insight on how to write an investigation report to ensure it fosters a culture of learning and development, and brings about positive change within your organisation which, after all, is the point of an investigation.

If you require our assistance when writing your investigation report feel free to get in touch or book a free consultation so we can discuss your needs.


What is an investigation report?

An investigation report is a formal document that details the findings of a workplace inquiry. It serves as a crucial record of the investigative process and its outcome. The report cleans up everything gathered during the investigation, presenting it in a clear, concise way for relevant decision-makers.

The purpose of an investigation report is to present a factual account of an incident or complaint, explain what happened, why it happened, and potentially who is responsible. It includes details like the nature of the incident, the date and location, the people involved, evidence collected (interviews, witness statements, documents, etc.), and the investigator’s analysis of that evidence.

The report culminates in conclusions based on the evidence and may include recommendations for corrective actions or preventive measures to avoid similar situations in the future.

Why are investigation reports important?

As workplace investigators, we know first-hand the power a well-written investigation report holds. It is the culmination of a great deal of hard work, and getting it right is crucial, for the following reasons:

  1. Maintains transparency: A solid report demonstrates a thorough investigation. It shows you meticulously followed procedures, interviewed all relevant parties, and gathered concrete evidence. This meticulousness is key. If you ever face legal challenges, a detailed report becomes your shield, proving the investigation was fair and unbiased.
  2. Paving the way for progress: This might be the most crucial point. The report isn’t just about what happened; it’s about what happens next. By outlining your findings and recommendations clearly, you provide a roadmap for positive change. Did you uncover weaknesses in a company policy? Highlight them and suggest improvements. This ensures the investigation isn’t just reactive, but helps prevent similar issues from cropping up again.
  3. Legal documentation: A thorough report, with its documented evidence, protects the organisation in case of legal action. It shows you acted in good faith and took all reasonable steps to reach a fair conclusion.
  4. Informed decisions: A well-written report empowers decision-makers. By presenting all the facts, you give them a clear picture to base their actions on. This can be anything from disciplinary measures to implementing new safety protocols.
  5. Building a Just Culture: A good report fosters trust. By laying everything out transparently, it shows employees the organisation takes complaints seriously and investigates them fairly. This builds a Just Culture – one where people feel comfortable raising concerns knowing they’ll be heard and addressed properly.

Remember, an investigation report is a powerful tool. Take the time to craft it carefully, and you’ll be laying the groundwork for a safer, fairer, and more positive work environment.


What is the structure of an investigation report?

When writing an investigation report there are certain steps which should be followed to help guide the reader through the process which took place. A logical and well-structured report helps to build confidence in stakeholders and reflects a thorough investigation.

It is important to introduce the report by summarising the investigation and subsequently expand on each area in greater detail so that the reader has the full information to hand in order to make a decision on the recommendations being made. The initial summary presents the outcome. The detailed report justifies it.

By fleshing out the points with evidence and analysis, the report strengthens the conclusions reached in the summary. This is crucial, especially if the investigation leads to disciplinary action or policy changes.

Here are the key sections of a strong investigation report:

  1. Executive Summary: This a concise overview of the entire investigation, summarising the key points – the nature of the incident, findings, conclusions, and recommendations.
  2. Preliminary Case Information: This section sets the stage and establishes the groundwork by providing details like the date the investigation began, the investigator’s name, and a brief description of the complaint or incident that triggered the inquiry.
  3. Incident Summary: This section sets out the ‘who, what where and when’ which is an important step in providing an understanding of the full scope of an investigation. Be sure to provide specific information on when the incident occurred, where the incident happened, and who was directly involved in the incident (list their names and titles/positions if relevant).
  4. Allegation Subject: Identify the person or department at the centre of the investigation. This section should also outline the specific allegations or concerns raised.
  5. Methods of investigation: Describe the investigation team, such as their positions and qualifications, and detail any site visits made during the investigation and any documents reviewed.
  6. Investigation Interviews: Write a report for each interview, including details like the interviewee’s recollection of events, their observations, and any opinions they expressed that are relevant to the investigation. Assess the credibility of each interviewee’s story, such as whether it remained consistent throughout the interview (internal consistency) and whether it aligns with other evidence gathered in the investigation (external consistency).
  7. Findings and conclusions: This is where you state the facts (not opinions). Based on the evidence you gathered, explain what you determined actually happened. Be clear, concise, and objective.
  8. Recommendations: This is all about moving forward. Based on your conclusions, propose specific actions to address the situation. If you uncovered policy gaps then recommend changes, and outline any disciplinary actions which were needed.
  9. Details and notes: Use an appendix to attach copies of supporting documents that are too lengthy or detailed to include in the main body of the report. Examples include interview transcripts, copies of emails, documents, or other relevant records, photographs or diagrams or expert reports, if applicable.


How to write an investigation report: Essential tips

As well as following the steps above here are some valuable tips to be aware of when writing your investigation report. All of this is essential for your report to be taken seriously and inspire trust in the reader.


Make sure you confirm whether the investigation finds the allegations to be substantiated, unsubstantiated or whether further work or evidence is required to make a decision.


Ensure the report is easy to understand so that the reader knows exactly what went wrong as well as what the recommendations are to prevent it happening again.


Keep the language simple and concise, and always use the evidence to back up your analysis.


Write using active voice (not passive voice) which gets straight to the point, emphasising who performed which actions. Sentences with strong verbs that identify the doer (subject) make the report easier to read and understand. Active voice projects a professional and confident tone and avoids the bureaucratic feel that passive voice can sometimes create.


Ensure the information contained in the report is organised so that it can be easily understood by someone not directly involved and without having to reference external materials. If possible ask someone else to read your report to confirm that it is clear and unambiguous.


Maintaining objectivity is absolutely critical for several reasons. It fosters trust, strengthens legal defensibility, ensures accurate findings, promotes fairness, and paves the way for effective recommendations. It shows the reader that the investigation was conducted fairly and without bias. This is essential, as the report’s findings could have serious consequences for people involved.


In summary

Sifting through evidence, structuring the narrative, and presenting objective findings to write an investigation report can seem overwhelming. But remember, this guide is here to equip you with the tools you need to navigate the process with confidence. By following these steps and prioritising clarity, objectivity, and a well-organised structure, you can transform your report from a simple record-keeping exercise into a catalyst for positive change.

After all, you’ve invested significant time and effort in uncovering the truth. Don’t let that hard work go to waste. Use your report as a springboard to create a more positive and productive work environment for everyone.

If you need help on how to write an investigation report, or would like to know more about our workplace investigation services please book a free consultation, or if you prefer, use our contact form, or contact Ed Marsden on 020 7494 5670 or [email protected].


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