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  • Why investigate? Part 2. Where do facts come from (mummy)?

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    This is part two of a series about the investigation process and human factors in healthcare. Part one looked at the why we investigate an ‘incident’ and concluded that there is only one reason to investigate – and that’s to stop the error occurring again. The idea that human factors is a science – done by science types rather than by (deep breath) public speakers, non-technical skills (NTS) professionals, those who create team talks, medics who have been on a course about being nice and polite to other medics, and those that have married a human therefore they must be qualified to talk about humans – was also discussed.

    This and the next blog will introduce the concept of where facts or data comes from. Later blogs will deal with the who, how, when etc. The ‘who’ investigates (next blog) really is determined by where the facts come from. Later – if the cake lasts – we can chat about what to do with the data, and how to report it and save lives.


    Mummy – Where do facts come from?

    Well dear, when two investigators love each other very much (well can tolerate each other’s company for long periods of time) they do an investigation and the product is facts. Like a small child these facts bring great happiness, sadness and often inconvenient truths! These facts are messy – difficult to rationalise, have a life of their own, and will be tested by others in what appears to be out of context tests and exams. When the facts are older, both investigators will realise that they should not have been collected in the way they were. By then the investigators have made other facts that may be different from the first ones.

    We need facts in order to say what happened, write a report and stop the incident re-occurring – but what sources of facts and evidence is there that are relevant? In this section, I’ll discuss some sources outside the patient’s hospital records, test results, and the paperwork of the ward and theatre. The audience will know what all these records are and for brevity I will not go into detail.

    Moreover, is there a method or position in which facts are best collected that is rewarding and satisfying (to the regulator or other parties)? Perhaps that’s another blog?

    If we understand where facts come from this determines who (what sort of person) should collect them. Like many things, collecting facts by yourself is not as rewarding as doing it with others. I can already hear a deep sigh as a nurse is reading this thinking – others – did he say others? – well it’s just me and I’ve 40 to do by the time I go home. With emotions raised about the next piece, let’s think about the sources of facts an investigation will collect, then the method or structure to collect them. Ideally, we should talk about presentation of the facts and how they are displayed and shown off to others – look at my facts here, are they not clever? But let’s do that in the three E’s blog later. 

    People – facts come from those present at the time

    Most of the evidence comes from those present or with some knowledge of the incident. Collection can be by interview, statement (oral and written), simulation... well loads of methods that try and recover a memory of an event, in the past, hiding in the mind. Noting here that humans are not video recorders and their memory is highly reconstructive and the worse creature on the planet to be a witness is a human. Humans also make terrible investigators, as they have biases and heuristics (more later when we chat about thinking and deciding in the human factors blogs).

    Interviewing witnesses is a skilled job but there are tools, techniques and methods that get ‘facts’ from inside someone’s head out onto your note pad – or recording device. There are three types of witness. Firstly, the person directly responsible (or who says they are responsible), there are those that directly observed the person who says they ‘did it’ and there are those who possibly noticed other useful facts – the security guard who noticed the arrival time, the HR person who interviewed the person the week before. Care needs to be taken if there is a chance of a criminal investigation, as the last thing the team needs is someone doing interviews that change the facts. Remember these posts are about prevention – not about criminal and civil liability matters.

    The tools and techniques tend to involve things like the Cognitive Interview. There are resources around that can help. There is an old NHS one – which hopefully has disappeared (by me ripping the leaflets up with my teeth) that says you ask the person to imagine the incident from another perspective. This of course we now know is the last thing to do.

    There are many blogs and posts I could write about the how to do an interview but look for a cognitive psychologist – PhD sort who does this area of memory research.  

    From science and previous incidents – books and Professor Google

    The incident or one similar would have occurred before. This means there is a court record of it or a lovely science type has written a paper about it. Now hanging my head in shame, us science types don’t write in peer-reviewed journal articles in an easy to understand way. But all us science types love people asking about our work. Rather like the spotty kid at the school dance – we won’t make eye contact, but if you ask us about what we are interested in, well there is no shutting us up. Email saying I would like a copy of your paper to the spotty – I mean science type - is what you do. My team – who do the real work and have the titles of Professor and have lots of chartered words on their businesses cards – also stress that you need to, and I quote  “and ask them to explain anything you don't understand" – they love that and it means you're not making any incorrect assumptions.

    Data and engineering logs

    Equipment when it fails tends to output data that is recoverable. The train I’m working on now records data every 1/25 of a second on every one of the driver inputs. In aviation, the flight recorder or black box (its orange by the way) measures the voice recording as well. One day healthcare will be there. But ask the question of its maker, what data is stored?

    Equipment operator manuals and testing

    Equipment sometimes, and in healthcare very occasionally, has been tested by a human factors type – ask the maker for the testing. This gives you an idea of how the medics dealt (or attempted to overcome) with its idiosyncratic ways. It sometimes seems that medical equipment is designed without much rigour.


    Spending two years of my life looking at CCTV images of a door in Paris means I think there is some value to CCTV ,and my work for HM Government on the subject does reveal its damn useful in finding the context of the event. Top tip is that data goes from a server after 28 days – so it’s one of the things to get quickly. There are CCTV experts, but a good dose of common sense means you will get lots of facts from it. Super, I’ve alienated another group of experts!


    Photos are your friend. Photos are useful in your final report and show things clearly. Now you are about to hear spinning forensic photographers. Yes, there are specialist courses on how to take pictures and what camera to use. But, here we go, a phone camera is all you need. If I’m found dead in an alley with witnesses saying there were camera flashes – then those who taught me the subject have read this. Pictures tell a story and collect evidence in more detail than a note pad. Perhaps one day I’ll do a conference presentation on the topic. But the top tip at this point is to have a measuring tape in any close up and tell a story with your images. More experts alienated.

    Expert evaluations

    Experts are useful. A human factors person is a must, but a medic from a similar discipline or someone from the Royal college is a great asset. Although I lectured in neuropharmacology for 15 years, I still always get an expert in this field to explain the detail. I choose this area as everyone I’ve asked has been brilliant. I start with "help me understand…".

    Simulation and reconstruction

    These are major sources of data. But three questions:

    • Why are you simulating the real world in a simulator – when it’s (the real world) out there?
    • What’s the fidelity of the world the simulator generates?
    • Who are your test victims - I mean participants?

    Healthcare is the weirdest place for simulation and exists in a world of its own. If you want to understand the issues, go to your local simulation suite and simulate nothing – aka a patient with nothing wrong with them – see what happens. A fiver says there will be hundreds of medical conditions found. It’s unlikely the correct conclusion that the person is well and asleep will be found. The problem is that aviation uses simulators (therefore they must be great), but these replicate the simple world of flying – aka stay in the blue, avoid green and land on the grey bits. Healthcare is not a simple world, its complex and we don’t know all the factors that you need to replicate or simulate.

    Simulation is a useful data collection method when you use people who were not involved in the original event. But those participating in the exercise know something is going to go wrong and have not worked the hours the team in the incident involved would most likely have done. I confess that in one of my published papers on fatigue the simulation was only 12 minutes long. But simulator time is expensive, and the pubs open at 16.00. Was the simulation good? Was there ecological validity in what I was doing? Well its published and other scientists thought it was ok. Oh, ecological validity – what you simulate or measure in a lab has something to do with the real world!

    Measuring things and testing them

    This is where my rail, road and aviation stuff comes in – I’m not sure why, but we always seem to throw one bit of metal at another and measure what happens. I’ve closed the centre of Croydon one night and threw black and white cars at each other all night. I’ve closed a motorway, caused chaos, and then the only thing the police remembered about the whole thing was driving along the closed motorway looking for badgers. Apparently, I do BF (Badger Factors). In the autumn I’ve learnt that badgers like the warm road and have a nap on the tarmac. Badgers are heavy things and if you hit them at speed you have another investigation to do. Testing to destruction gives loads of data, but the question before doing it is: what data do I get? – and are the badgers safe afterwards?


    Data, facts, and evidence are vital to the investigation – that’s why you do it – to get facts. But a simple change in method or just the use of one word in an interview will change your outcome. Mummy may have explained about how two investigators love each other lots – but there is always a bigger picture.

    Is there a method or procedure that’s good? Yes, but that’s for another blog. But a quick search about the police methods (SIO) and the road death investigation manual might get you ready.

    Read the other blogs in this series

    About the Author

    Martin is topic leader for the hub.

    He founded the Human Factors group at the University of Sussex (1999), which became User Perspective Ltd in 2003. Martin, User Perspective MD and Chief Scientist, aided by his team, has undertaken almost 600 research and forensic investigation projects. He is interested in human error and human factors.

    Martin is a research auditor for the UK government, EU academic networks and many governments worldwide. Within healthcare he has investigated matters as diverse as neonatal safety in transport, unexplained injuries in the hospital mortuary, sepsis diagnosis and retained instruments. Martin co-authored the very first Healthcare Safety Investigation Branch (HSIB) report that investigated orthopaedic surgery in the UK and Europe. His interest in the law and justice extends to his voluntary role as a justice of the peace (JP) in the Magistrate and Crown courts.

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