How to Write an Investigation Report

Nobody likes writing investigation reports. Nobody really likes writing anything; this applies to professional writers as much (if not more) than to the rest of us who have to write to communicate, on top of our other responsibilities.

Fortunately, there are some ways of making it a relatively painless process – and a good thing too, because writing the report is absolutely crucial to any investigation.


In fact, you wouldn’t be far wrong if you defined the investigation report as the most important component of your investigation. It’s the bit that communicates your findings. The bit that explains what went wrong. The bit in which you express your recommendations.

And the bit which can change the future – for the better.

That, after all, is the whole point of investigating in the first place.


The first thing to remember is that when you’re writing an investigation report, you’re trying to persuade someone to do something. Just like an advertisement or a direct-mail shot, you want the reader to get to the end of your report and take action.
In this case, the action is: to put your recommendations into practice.

Before your reader can do that, therefore, they have to be persuaded.

And to be persuaded, they have to understand.


We’ve all seen that sort of writing:

For the purposes of a non-pre-scheduled process of elective rehydration by means of the ingestion of a pre-prepared alkaloid infusion delivered by an on-demand user-operated dose-consistent process, the victim was of necessity engaged in a stepwise incrementation of his personal potential energy quotient by means of a progressive elevation of his bodily mass using a pre-existing manual-process “step-and-riser” system originally installed at facility commissioning in accordance with standards then operative in workplace standards & facilities standards currently pertaining. During this process, said victim 
experienced an unpredicted decrement in personal adhesion due to a local area of out-of-specification frictional coefficient due to an adventitious “pooling” of non-pre-admixed solvent designed for subsequent admixture with an anionic/amphoteric surfactant product by a routine preventive anti-contamination operative, leading to said adhesion falling below the stress/shear tolerance necessary for the continuation of the said process. This was followed by a rapid non-linear reduction in potential energy and the resultant transductive process caused the application of kinetic but non-fracturing shear stresses to 
the victim’s dextro-patellar region and subsequent contusion and minor haematoma…

By which time you’ve long ago lost them. Easier, and just as accurate, to say:

The victim of the incident was going upstairs to get a coffee from the machine when he slipped on a puddle of water left by a cleaner and fell downstairs. He banged his knee in the fall, and bruised it.

..which is, of course, precisely what our phantom investigation report-writer would say if you asked them, face to face, what had happened. People often write in an over complex, jargon ridden way because they think it sounds impressive. It doesn’t; it just confuses and irritates.

So, in general, the rule is simple: write it as you would say it. Writing isn’t magic. It isn’t special. It’s no more than a way of allowing people to hear what you are saying without being there while you say it.

We can break this down into a few simple components:

1: Keep it simple. That’s self-explanatory.

2: Avoid jargon and pomposity. Don’t forget: not everyone reading your report will be an expert in your field. They may not know the jargon. It doesn’t mean that professional jargon is wrong; just that it’s specialised. In an investigation report, write for the non-specialist. As for pomposity… have a look at what you’ve written. Does it come across as really serious and important but you can’t tell what it means? Okay: it’s too pompous. Simplify. Talk straight. Plain words.

3: Keep It Active. Don’t say, “The man was bitten by the dog.” Say, “The dog bit the man.” The first way is called the “passive voice” and usually is a way of keeping yourself at arms’ length from what you’re saying. The end result lacks conviction and is unpersuasive. Which – since you’re writing to persuade -you don’t want.

4: Short Takes. This is an old newspaper anecdote. Reporters used to write their stories a sentence at a time. Then they’d hand it to the copy-boy. One sentence contained one statement. One paragraph contained one idea.

For the next idea, they’d start another paragraph.

It worked for them.

It still works for them.

It will work for you.

For example:

‘Bart Simpson, aka Nancy, Booked for Fringe’

Bart Simpson is to appear at the world’s biggest arts festival this year, it emerged yesterday’. Nancy Cartwright the voice behind the cartoon character, is to launch her debut one-woman show in Edinburgh this summer. The three-week run will be based on Cartwright’s best-selling memoir about her role as a spiky-haired tearaway, ‘My Life As A Ten Year Old Boy’. Her performance at the Assembly Rooms in August is expected to be one of the Festival’s hottest ticket sellers etc.
(‘Aberdeen Press and Journal’ – Feb. 4th 2004)

5: Get A Second Opinion. If you can get someone outside your investigation, your department or, best of all, your industry, so much the better. If you can get a reasonably intelligent 12-year-old to read it, better still.

The average senior executive wants something straightforward and unambiguous. That doesn’t mean they are stupid. Far from it; it just means that reading dense texts isn’t one of their skills. And why should it be? Nor do they have the time.  We understand, of course, that in many cases there are other considerations. Legal implications. Confidentiality. Trade secrecy. Fair enough; but, all the same, you will be able to find someone to cast an eye over your report, for sure. So please do so.


The other main thing which will help you write clear, pain-free, persuasive investigation reports is following a clear and logical structure.

By this stage, you’ll have all the facts (or at least all the facts you’re going to get). You’ll understand the timeline and the sequence of events. You’ll have worked out your root cause analysis. And you’ll know what your recommendations are going to be.

So where do you start? You may have a company reporting form where you just fill in the blanks. In that case, fill them in. Or you can use our Reporting Template.

On the other hand, your investigation may be too complex to fit on the standard company form. What do you do if that’s the case?

Here’s a simple structure which will help you get the information across in a clear, logical and persuasive way. It’s not something we’ve made up. It’s standard. And we suggest that, if you follow it, you won’t go far wrong.


In the summary, you explain briefly:

– Who was involved in the incident
– What actually happened
– When it happened
– Where it happened and
– Who you are (and why you are investigating it)


In this section, you give a broad overview of WHY it happened. Summarise the immediate causes and the root causes and anything else you think is specifically relevant, but don’t go charging off into detail. That comes later.


In the Recommendations, you are simply answering the question, “What now?” You might recommend changing procedures, re-training someone, installing new equipment; whatever it may be. For the sake of clarity, we suggest you link your recommendations with the causes which prompted them.

For example:
“Root Cause #1: Driver of the trailer to be retrained. (Has ‘can do’ attitude and reluctance to listen to advice.)

Then your reader can not only see what you recommend, but why. Giving the reason makes it much more persuasive.


Now we come to writing the main body of the incident report. This expands on all the points in the initial part of the report. It, too, falls into clear sections, as follows:

1: Aims & Objectives
Tell the reader what you were trying to do in the investigation (e.g. “The investigation was designed to get to the root causes of the fire in the Loading Dock”) and what you hoped to achieve by doing it. (e.g. “We intend, by addressing those root causes, to prevent similar and related incidents happening in the future.”)

2: Incident Description
Describe precisely what happened, beginning with the initial incident statement and resisting the temptation to launch straight in with underlying or root causes or inappropriate detail. They come later. At this stage you should be objective. (e.g. Incident Statement – “Train ran off rail. Damage to property and potential injury.”) The Incident Description expands on that adding the rest of the detail which is 
known to be true.

Make sure you cover the Who, What, When and Where in your description, and add any significant and immediately striking factors which are known to be true. But this is not the place to go into your methods of investigation or your findings. They come next.

3: Methods of Investigation
Begin this section by describing your investigation team: who it was made up of, their qualifications, their positions and anything else relevant about them.

Next, detail any site visits you made. Attach any photographs, diagrams or drawings you may have — but remember: many people aren’t skilled at reading engineering drawings or technical diagrams, and they may need some explanation.

Summarise any findings you may have made concerning documentation. You don’t, though, need to include all that documentation. It’s enough to say, “Permit to work had expired the previous week”. Just make sure you can locate it – or a copy of it – if you’re called upon to produce it (or you can include copies of documents, photographs etc as appendices).

Summarise, too, the results of any interviews you conducted. Who did you talk to? Where? What was the relevant information the interviewee gave you? Again, no need to include the whole transcript or detailed notes – just be sure you can lay your hands on them if 
necessary. In all these cases, it’s worth noting the location of supporting data in your report; in the future, another investigating team may want to consult your own records and it will help them if they can find them as easily as you can.

This section should also contain a summary of the details and the results of any simulations, tests or reconstructions you did in the course of the investigation.

4: Findings
This section is – as you’d expect – where you set out your findings. There are plenty of perfectly good ways of keeping your findings in some sort of logical order. The main thing is not to jump around all over the place like a cheap detective story; that just confuses. We find that ordering our findings in accordance with the TOP-SET headings is extremely helpful:

T ime, Sequence and History
O rganisation / Control / Responsibility
P eople and their involvement
S imilar events
E nvironment and its effects
T echnology, equipment & processes

We’d suggest you use these as sub-headings when writing your investigation report, and you may even want to put your findings in the categories of the planning chart you will have used on the course.

Having set out your findings, also – as in the introductory sections – set out your:

5: Recommendations
In this fuller version, you will want to address not only the root causes but also all the individual contributory causes you found along the way; they have to be dealt with also. In any case, once again, we suggest you tie in your recommendations to your findings and classify them under the TOP-SET headings/sub-headings, for clarity’s sake.

For example: T.3 Operating instructions or P.2 Activities and Tasks


We would seriously suggest that when writing an investigation report you should attach, as an appendix, a clearly drawn root cause analysis chart. This will clarify everything you have said in the previous pages of your report, and, as you yourself will have seen, a well-drawn-up root cause analysis is something that even someone completely unfamiliar with the incident can come to afresh, read through, and understand.

That’s all there is to writing an incident report.
Follow this structure and much of the drudgery will be taken out of report-writing

Want to learn more about how to write an investigation report? – Buy The Practical Handbook of Investigation – A fantastic resource packed full of hints and tips designed to aid any investigator.

Contact Info

Please don't hesitate to get in touch with any questions, to make a booking enquiry or to arrange for a presentation to learn more, and our team will get back to you shortly.

Head Office

USA Office

Let's talk

Share This