MartinL

Let's start with a summary of where we are in the blogs. I’m told our reader likes the summary (a Mrs Trellis of North Wales). In part one we decided why we investigate an incident and what an incident was. In part two we decided that two investigators (or more) collect facts together in a more accurate way than one would. In part three we gazed into each other’s eyes and concluded that facts are our friends and where they might come from. We decided interviews and photos give us good facts. In part four we were introduced to what human factors is, and what it is all about and how western psychology is about exploiting the worker! In part five we thought that facts are time dependent and men of my age should not wear shorts outside a restaurant/come damaged aircraft. We discussed how dependent witness memories are on the elapsed time for the effective retrieval of information. These blogs, therefore, are asking simple investigation questions of Who, What, When and Why, and basic questions about what can humans do (human factors). So here we are back to the powerful question ‘Why’ but this time, rather than "why investigate an event?", we are asking "why did this event happen?". Most investigations stop at the point of understanding how the person was injured or died. The how they died does not give you enough data to prevent it occurring again. Knowing, for example, that an elderly, lone rail passenger unfamiliar with the station died from head injuries after falling on a platform with the investigation team concluding that ‘they lost their balance and fell backwards’ does not help understand why this happened or how to prevent its reoccurrence. Why did it occur that day, to that person, on that platform? Might an intervention based on the question ‘How’ be that no one over 60, who is unfamiliar with the station and travelling alone, be prohibited from travel. The important question is why and not how. Likewise, a pedestrian is found dead by the side of the road after a collision with a van. How did they die? Well head trauma after collision with a van. How did that occur? The driver said that at night it was too dark to see the running pedestrian. Indeed, at the reconstruction it was very dark. But after 25 questions of ‘why’ came the critical ones. Why was a person out running in near total darkness without a light? Why could the van driver not see them? Why was there no light (torch etc) found with the pedestrian so they could run without falling into the numerous pot holes? Why that van and why that pedestrian. The why (in this case) comes from human factors research into perceptual thresholds of how much light needs to hit the retina for the cognitive process to start. Long story, but the answer to why was a murder disguised as a traffic accident. Which takes us back to my first blog – what’s an accident – this was not a rare random event with multiple causes. It had one cause – top tip sleeping with a colleague’s partner is not a good idea. Unless you answer why, then there is no intervention and that ‘why’ is ‘why’ we do this. Becoming a 5-year-old The skill of an investigator in human factors is to keep asking the question Why (and perhaps not to insist an infographic is needed). Like my 5-year-old self. Why can’t I ride my bike to the next town… But why, but why. The police car brought me back last time – I was not lost. This may explain why a disproportionate number of my friends are clinical psychologists! Case studies Two case studies. Let’s stick to rail. I can do why are anaesthetics rooms so small, but I’ll get all emotional! If I’m found dead in an alley it’s a hospital facilities manager wot did it. Case One A train station where there are 17 serious incidents on a single set of steps down to platform 1. It’s a traditional Victorian design urban station with access at street level and platforms below the booking hall. All platforms are connected by a glass overpass. No other platform (there are six) has an issue. One case is a fatality. How did they occur? The answer is – the person fell down the stairs. Head injuries and broken legs (not the same person!) are common. The ‘how ‘is answered. The why is not. Why did they fall down the stairs we asked. “There are stairs and people will fall down them” came the reply. Why? “Well there are stairs and people will fall down them”. But why these stairs, why this platform, and why 17 people? Well, came the reply, we will have to put a poster up telling people ‘these are stairs.’ Why did they fall we asked? We have a poster telling people how not to fall down them and how to use stairs (hold the handrail) they replied. We asked as a five-year-old would – why do you think these people have problems with these stairs? So, let’s think of the why questions after some facts. Might be worth also predicting that posters are the sign of defeat and result from only asking ‘how’. Also, putting posters above stairs, so that people look at them and not the stairs, is another classic failure of understanding human performance. Some facts Timetable information shows platform 1 is the city bound platform. Observations indicate that people descend the stairs very rapidly when there is a train present at the platform. Secondary observations come to understand that running starts at the ticket office overlooking the glass passageway over to the platform. Incident data reveals peak at rush hour above that of exposure (rise in passenger numbers). Only platform 1 can been seen from the walkway and the ticket office. The ‘why’ hypotheses was that as people became aware of the train arriving at the city bound platform, they made a run for it. We interviewed several of those injured. Most common statement from the predominantly local people was “I knew I would miss the train as I could see it at the platform, so I ran”. The remedy was to put plastic obscuring film over the glass walkway so you could not see if a train was at the platform. No cognisance of a train’s presence = no rapid stair descents. Only journeys into the city appear to be highly time dependent. Outcome After 11 years, no incidents on the stairs, no aggression to the ticket office staff (give me my ticket now!) and posters removed. Why – we asked ‘why’ not ‘how’. Removing ‘safety’ posters is always a good idea. I’m still trying to find out what an internal brand consultant is – they were against the removal of posters. Answers if you know what these are and how they make the world better please. Case 2 At a train station, there were 27 falls ‘down the steps’ of which four were citizens from the USA. These citizens of America are after the compensation for ‘foreseeable’ injury in the US courts. Think expensive when compared to compensation claims in the UK. As above, ‘the how’ was they were injured by a fall. Why at this station? Why these people? Some facts Incident data revealed all those falling down the stairs were visitors to the area (based on address supplied). Plans of the Victorian station reveals it’s a small (four platform station) with over 80 different exit route combinations, via three underpasses. Exit here is time-critical – it’s near an airport with a connecting bus. There are over 130 signs containing over 900 words of advice. Observations and interviews showed that perhaps passengers lost spatial and situational awareness (more in later blogs) and became disoriented. CCTV images showed one passenger was walking up and down the platform twice, then walking through one of the underpasses six times, before they injured their arm when the bag got caught in the handrail and they ‘went down, way down, the steps’ ( from Incident report). Our initial hypothesis was that a lost and disoriented passenger with bags will find stairs more of a challenge than one who is not. Remedy We removed most of the signs on the platforms and underpasses and replaced with one type of exit sign. Whether its exit to the airport or exit to the pub it’s still an exit. Locals – not represented at all in the data – know which of the combination of exits will get them to the pub. Outcome No incidents in 12 years, and the platform staff last year took rail executives around ‘their’ station telling them how easy it was to prevent slips, trips and falls because “someone asked why”. Why, and multiple causes Early on in our blog life together we said that accidents have multiple causes. In healthcare we are not sure how many variables there are and even the extent of the problem. We also described that the cause is about the ‘environment’, the ‘human’, the ‘system of working’ or the ‘equipment’. We decided together this determines ‘who should investigate’. Engineering failings are done by engineers, for systems failures investigations by nursing staff are recommended. Well here the ‘Why' word repeated on the first day is the solution to find out who should investigate. When do you know you have possibly stopped asking why too early? The common reasons for stopping asking the question ‘why’ is when you get to one of the following conclusions: 1. Its human error. 2. It’s the person who had the incidents fault – but remember organisations fail not people. If you get these conclusions, keep going and ask your friendly human factors person for help. Remember, one of the limits of investigations is that you can’t ask questions about things you don’t know about – obvious really, but that’s why there should be two of you and perhaps one of those is a human factors person. A major failing in root cause analysis is this fact is always overlooked. 3. I cannot ask ‘why’ anymore without getting asked to leave the building/the NHS/the human race… The solution is to ask questions using the Socratic method. More later when we think about logic – but the Greek philosophy types nailed it many centuries ago (just like they invented human factors in medicine; ergonomics they called it). Citing Professor Wiki once more and to appeal to the midwifes among you, the Socratic method is: “a form of cooperative argumentative dialogue between individuals, based on asking and answering questions to stimulate critical thinking and to draw out ideas and underlying presuppositions. It is named after the Classical Greek philosopher Socrates and is introduced by him in Plato's Theaetetus as midwifery (maieutic) because it is employed to bring out definitions implicit in the interlocutors' beliefs, or to help them further their understanding”. Again, this is part of the human factors persons training and why we ask the questions in the way we do to members of the investigation team (sorry). There is a management consultancy (boo hiss) methodology called the ‘5 why method’, and its creeps into the root cause analysis nonsense (more boos). But just asking why without the Socratic teachings tends to just annoy people. Exploring ‘Why’ as an equal to the person you are talking to is more respectful and gets better data, and you should not get thumped. Who asks why and to whom? In later blogs we shall chat about interviewing witnesses. This blog is about the internal dialogue in the investigation team or, if there is just one of you, the internal monologue. Asking why to a witness is generally not the thing to do. Its common in healthcare but the witness cannot report Why, they only know the How. Witnesses provide facts, the team finds answers from those facts ('Where do facts come from?'). Summary The ‘Why’ word is very powerful when added to a blank sheet of paper and a pen in the hand of the investigator and means that you focus on the outcome and not on a process. As replies to my earlier blogs – about how healthcare is all about process and not outcomes – well one word and some paper mean you can just focus on prevention. And dear reader why we investigate is to prevent it occurring – in the words of Metallica – 'Nothing else matters'. And finally... The station (discussed above) where elderly people represent the dataset. All falling backwards on platform 1 and our initial (yours and mine dear reader) remedy was to exclude over 60s from it unless they were trained. Suggestions of why and what questions would you ask. Comments below. Top tip – no one was running and all very cognisant of the train times, and all but one sober. Happy if you want to test out the Socratic method now. Posters, as a solution, are not permitted. Read Martin's other blogs Why investigate? Part 1 Why investigate? Part 2: Where do facts come from (mummy)? Who should investigate? Part 3 Human factors – the scientific study of man in her built environment. Part 4 When to investigate? Part 5

The story so far... We investigate an incident to collect facts that will prevent the incident from occurring again (see 'Why investigate?' blog). Facts collected by two or more investigators, with enough time away from the ‘day job’, tend to be of better quality than a single person fitting the investigation in and around their other duties (see 'Who should investigate?' blog). Human factors is a science done by science types who are trained in understanding how the limited ‘cave dweller’ tries to cope with their environment. Human factors types are not likely to have the title ‘Captain’ and have not just landed at Stansted (see 'Human factors' blog). Facts are our friend as they allow us to tell people why an incident occurred and, if those facts are accurate, allow us to do an intervention that will prevent the incident occurring again (see 'Where do facts come from?' blog). Good facts and great remedies allow us then to monitor the success of the intervention. But again, we are getting ahead of ourselves by talking about interventions. Sorry. At this stage it might be worth thinking about what we do with all those facts, how we see patterns in the data, what a good intervention might look like, and how and when we monitor success. As we have seen previously, there are four principal areas where facts come from: the human, the equipment, the environment and the system of working. How the investigation is conducted and by whom, and as we shall see ‘when’, affects these four principal areas of investigation and the three methods of intervention. So, four areas of investigation with facts emerging from many different sources: from inside the witness’s mind, from ward records, from engineering logs, etc. How these facts come together to form a big picture needs to be considered in terms of the intervention. A later blog will explain these interventions (after we discuss data and analysis – yay statistics), but for now it’s worth saying the three interventions are called ‘the three ‘Es’. Luckily the three words all start with the letter E so it makes sense. Engineering – The most effective intervention, as the machine keeps the cave dweller from making mistakes. Enforcement – Where someone polices the method of working or the equipment used, in a given environment. Education – the least effective method, which relies on a training course or a poster. “Don’t operate on the wrong side of a patient”. Well I never, what a useful reminder in a theatre. My favourite was at a rail depot. A poster (1 of 80 in the area) said. “Be alert and check the doors”. Really closing the train doors is a good idea… More in the intervention blogs. The why, the who, the what data collected will affect the quality of the facts. The facts collected determine the intervention chosen. The monitoring of success of the intervention is, perhaps, determined by the original hypothesis of the investigator, very early on in the investigation. We may do a blog on bias in investigations. A word of caution. You don’t always do an intervention. ‘Eek’ I hear screamed from every trust. This is because, as we have discussed, an incident is a rare random event with multiple causes. Sometimes an incident, or series of incidents, have occurred due to the random nature of humans and an emerging pattern of data is thought to have been found. This pattern, and these series of events, are, however, just random. So, very early on in this blog, I introduce the idea that ‘when’ an intervention might occur might be never. An example… Lots of crashes occurred along a three mile stretch of road. Detailed investigations revealed no pattern in any of the crash’s causation. The local authority had over £3 million to spend and was determined to spend it (they rightly want to keep their community safe). Well what intervention would you do given that there is no pattern? There is no consistency in the facts and the only pattern might possibly be in the investigators' minds. Given accidents are rare random events, if you do an intervention will it not make it worse? If it makes it worse, how do you reconcile your ‘no pattern data’? A comment was made by the local authority that suggested a pattern existed and we were not good at investigations and human factors. We reviewed the data again and conducted interviews with those involved (at our own expense). Indeed, there was perhaps a pattern. If you were female (most were), you were travelling north (most were), you were in the early stages of pregnancy (most were) – you appear to be involved in a crash. We noted this at home visits and it’s not recorded in the police data. Upon reporting back, the local authority understood that incidents are indeed rare random events and sometimes data emerges with no explanation. The comment from the authority – “So the only intervention is planned parenthood advice a few days before undertaking any northbound journey?” Indeed, that’s the correct conclusion for the data. No intervention was undertaken, and seven years later no incidents have occurred, and we understand the northbound mummies and babies are doing fine. The local authority remains a client after 18 years. It might be the case that (as my reviewer points out) that “maybe there was a factor there, but it went away without intervention (sleepwalking cattle randomly moved to another field further from the road)”. Hopefully, that should show the connection between the philosophy of data collection, its method of collection and by who, and how it affects the intervention and prevention. Also, the benefits of planned parenthood when travelling northbound. Hopefully, I’ve rounded up the last four blogs. So it’s now time to look at the when; like parenthood, it affects the outcomes too! When to investigate? When to investigate is determined by the facts you want to collect, where those facts come from and whether those facts are time sensitive, and your availability and the accessibility of the location. In broad terms, the ‘when’ is affected by two types of evidence: physical stuff and human witness stuff. Physical evidence Let’s start with a photograph. (Warning the image below contains graphic depictions of an older man in shorts!) Image 1: Older man finds the remains of an aircraft converted to a bar and restaurant. Copyright: User Perspective Ltd. Recovering engineering or physical evidence is less time sensitive than information from witnesses. Ward records can last a long time and engineering logs can as well. If you collect evidence from CCTV – that has a life span of 30 days. Generally, in medicine physical evidence is not time sensitive. However, like the image above, it shows that if you leave evidence for long enough someone will change it. In this case they make it into a restaurant. I eat elsewhere as I was sure a fellow human factor person was looking for the crash site! Human stuff – witnesses Most of the facts you collect come from witnesses, aka humans, aka cave dwellers. As we shall see in the ‘how to interview’ blogs, the facts are contained in the mind and it’s not easy to get them out. As you can see in Image 2 below, the decline in the availability of facts is very severe after 20 minutes. In later blogs we can discuss how to interview witnesses and how to get good quality data. Image 2: The Forgetting curve 1885. Copyright: User Perspective and HM Government (for this version). The important bit now is to think about the basic processes of human memory, which are: Perception – information gets into the mind. Encoding – its related to other facts and ‘digitised’. Storage – we need to keep it somewhere. Retrieval. Unless it can be extracted, it’s not useful. Each of these stages is associated with a decline in the quality of data and its retrieval is based on the ability of (in this case) the interviewer extracting it. As we are talking about when, the important thing is to get to those memories as quickly as possible and, certainly in medicine, to ensure that witnesses don’t get to chat to each other. If you want evidence from humans – get it quickly and ensure they don’t talk to each other. How quickly? It’s called the golden 24 hours in accident investigation – even though the graph from 1885 suggests a lot shorter time span. Incidentally, the person(s) reporting the incident needs acknowledgement a lot quicker than the 24 hours. Your availability and access Ideally you are a human factors person with a ‘go bag’. I’ve several ‘go bags’ that contain equipment needed for each domain (road, rail, security) I work in. The road one has green high vis, the rail has orange. The security one has assorted passes and body armour. This may be different in medicine. You might not be the first person called, and you work shifts, the chances of a call in the middle of the night is most likely rare. In other domains access is aided by blue lights and the possibility of handcuffs. Healthcare is different – remember these blogs are about prevention rather than prosecution. However, the point is that every second counts and the sooner you are there the better the data. Summary The facts you collect, how those facts are collected, and by who and when, affects the conclusions you can draw about the incident. Physical data lasts longer than human memory data but, as the picture of the ‘converted’ aircraft shows – things change. Who and when the facts are collected affects the interventions you can use, and the reliability of testing those interventions you trial / test. Human factors people or psychologists are a vital part of the team. They are only part of the team. You should see a pattern. What evidence (when it’s done and by whom) you collect, affects the intervention and its success. With no data you should not do any interventions. Indeed, without data you may not wish to. Remember it’s about outcomes and not just documented processes. In the words of the philosophers – Metallica – “nothing else matters”. Next time... Human factors part 2, or should we do interventions? Like the Star Wars films, these blogs may appear in the wrong order but the final box set hopefully makes sense! Comments welcome young Skywalker. Read Martin's other blogs Why investigate? Part 1 Why investigate? Part 2: Where do facts come from (mummy)? Who should investigate? Part 3 Human factors – the scientific study of man in her built environment. Part 4 How or why. Part 6

Humans have not evolved to do medicine – or deal with complex machinery or systems. For the average (HF) scientist, it’s amazing how few errors occur and how a disinterested cave dweller (aka human) can work 12–18 hours, operate a machine (in many dimensions), and still get home safely at the end of the day. A short history of human factors HFs is a subdiscipline of both engineering and psychology. In respect of the psychology element, it is in the tradition of western performance measuring psychology. This measurement aims to aid productivity by identifying the best of the higher performing ‘cave dwellers’ for specific tasks. As we have all essentially evolved in the same ways and are not too far removed from our cave dweller ancestors, we should aim to design equipment that we can use now rather than waiting for evolution to enable us to use the kit. In this respect, HF is vital. In contrast to the western approach, the Soviet psychological tradition considers that all of us can be elevated to do any task. The background of this was that when the former Soviet Union industrialised rapidly in the 1920s they could not find the best of the higher performing ‘cave dwellers’ – as the majority were illiterate agrarian peasants. In the West, industrialisation was slow and there was time to find the best. A good example to illustrate this is the space programmes in the West compared to the Soviet Union. The United States tested people to find the best in the military whereas the Soviet Union advertised in the cotton mills “cosmonauts wanted”. Many say the Soviet tradition – also found in Scandinavian countries and in much of northern Europe – is a fair, humanitarian, way of thinking about humans, and the western method is there to divide the workers by exploiting them and getting them to produce more. This may explain my attachments to European medical establishments where I find everyone is happy! HFs is concerned with understanding how us ‘cave dwellers’ use our limited physiological skills and cognitive resources to achieve a task. The science is basic in that it attempts to understand, in principle, things like how our senses work, how our brain/mind filters the vast amount of information heading through those senses into the mind, and which bits are selectively attended to (or not). Humans tire easy, lose concentration, get distracted and are not exactly rational. Medication affects us in many ways, and aging and experience adds to the mix of human performance. That’s what HFs is about. If you ask in medicine, it’s about teamwork – or Crew Resource Management (CRM) – being nice to someone will stop any incident occurring. It’s non-technical skills – the idea that by watching someone’s behaviour (after expensive training) you can then understand their inner most cognitive processes and intentions. Or many different types of ‘psychobabble’, pet theories or simple weird ideas. HFs, being a science, relies on evidence and testing, and is interested in performance. HFs started not on the flight deck, or on the battlefield, but in medicine some 2000 years ago. The first HFs scholar was most likely a Greek doctor – him of the oath you all swear. He discusses how, for efficiency, tools and equipment are laid out in a way that is easy to use – that’s HFs or, as we have also borrowed from the Greek, ergonomics! Most likely one cave dweller preferred one rock over another. Of course, the one that preferred the apple as a communication tool was way ahead of their time! Subdisciplines of human factors There are subdivisions within HFs worthy of note as useful to medicine. These were hinted at in my last blog. These are human computer interation (HCI) and human machine interaction (HMI). Each group has its specialists. Often you don’t need a HFs generalist, you want an expert fully trained in one of these areas. An example of the difference in these subdisciplines can be illustrated in a crash involving a plane and a tug (thing that drags a plane around an airport). An HCI person looked at the screen bolted to the tug where information to the driver was displayed. Incidentally, HCI people are sometimes called UX (User Experience) designers. The theory was that the tug driver was distracted by the screen. It was fine. The HMI specialist said it must be the whole machine – the controls, the visibility from the driver’s seat – but all was fine. The HF person asked the tug driver, after doing the first two lots of tests again (HF people do things twice), when did you last see a medical professional? The answer was the day before; that he had ”some jabs ready for his holiday”. The HF person was shown the leaflet given to the driver after the jabs, telling him that he might feel dizzy or tired and not to operate heavy machines. The driver did not think an aircraft under tow was a heavy machine. HFs is, therefore, the study of the man, and the system, and the built environment which she is working. To relate this to the above about western psychology, HCI is often based on Soviet psychological testing. Rapid onset of computer and screen technology meant everyone was a naïve peasant again, with no clue how to operate the machine, or to get the Bluetooth to connect in the car! The answer of course is to use both traditions. The senses Let’s make a start about thinking about HFs. The history is important as it frames the study. Let’s think about the senses. Seeing hearing, feeling, tasting and smelling. If we start with the basics, then perhaps we can think a little about all those higher cognitive levels that the medical profession thinks HF is. Perhaps a bit on fatigue and attention as well. The senses tell us: What is out in the environment. How much is out there. Is there more or less of it than before. Where is it. Is it changing in time or place. Seeing We have evolved to operate in daylight, not at night; unlike almost all other animals we have detailed colour vision. But there is no zoom lens – we need to get closer to see the detail. Our vision is perhaps optimised to find ripe fruit in trees. Our field of view is extremely limited – or more precisely our ‘useful field of view’ is limited and in general we can only ‘see’ things we are directly looking at. Although our vison is very limited, it’s further reduced as the signal from each eye is split and sent off down different channels into the mind where it arrives as a blurred upside-down image, via the retina, and the brain has to interpret what’s going on. Vison is more about conception than perception. That’s to say the mind controls what we see to such an extent – and this control is based on experience and expectation – that vision is limited. The fact that there is something in the world that can be seen and could be identified is only a tiny bit of the picture (pun intended). The scary fact is that 95% of the information we use about the world is visual, yet we don’t have good vision. Well fruit picking is fine, but dealing with neurological conditions – no. A lot of medical packaging and its very poor labelling can’t be seen, let alone comprehended. Even in the test lab – let alone in the theatre with its weird lighting. Hearing The story gets worse – the good news is we don’t rely on hearing as much as vision. Humans find it difficult to discriminate sounds of voices from other voices and with noise in the background. Sound waves work in weird ways and you can have a negative (inverse) sound wave that cancels out the one you are trying to detect. Think noise cancelling headphones here! Taste, smell and touch These are minor senses when it comes to the overall picture of the world we need to form in our minds. Remember we are talking medicine rather than restaurant critique. They are useful. Warnings that use vibration (e.g. stick shake in a cockpit) work better than other audible warnings. I might do something on the psychology of warnings in a later blog. Investigators spend the majority of time trying to understand if the senses of the 'cave dweller' could have correctly detected and understood what was in the environment. Typically, the answer is no – that’s why it occurred. People rarely set out to have an accident, injure themselves or injure others for no apparent reason. Before the investigation team considers if higher cognitive factors like reasoning are to be thought about, you need to be sure the senses detected and correctly identified what was happening. Attention Psychologists since Greek times recognised the two types of attention mechanisms. One selective, the other sustained. Attention is the mechanism us cave dwellers use to filter out the overwhelming volume of information so we can attend to a bit of it over all the rest. The cat is reading this and also attending to the squirrel outside. If we were cats, I would not have had a job. Selective: Selective attention is where you rapidly need to selectively attend to one stimulus in the environment above all others. This is usually a product of visual search where we are looking for the thing to attend to – this can cause us to experience spatial uncertainly. The idea is that the ‘target’ will appear somewhere at some expected point (this relates to how our brain interpret things and based on expectations). Sustained: As the name suggests, this kind of attention investigates how long an operator can detect an event that is expected. Most of the research was conducted in the 1950s and investigated how reliably an American radar operator can watch the screen to detect a Russian aircraft. What we know about vigilance and monitoring tasks is that humans are very poor at it – we miss things very easily. Fatigue At the very first medical conference I went to, the A&E (ED) doctor who runs classes on HFs said he made errors due to not checking politely with his colleagues about his actions and then he spent 20 minutes talking about how pilots communicate. He then described his typical 18-hour day. At the question sessions, I asked if all his failures were not perhaps due to fatigue – and his answer was no. My second question was how often a pilot would do a shift of 18 hours and would you get on his plane if he said – “well I’m almost at 18 hours, I’ll give the landing a go”. Fatigue is time over 8 hours depending on the task. Times start from the moment you start for work – so a surgeon who drives 2.5 hours, does operations for 15, and then drives home for 3 hours has a long day. Fatigue is the hidden killer in medicine. Scheduling 12-hour days – well it keeps investigators in work. Fatigue is reduced by sleep and rest. Top tip – look at the quality of the sleep. “I’ve a young family”, “I was stationed at the end of the runway” is a good clue. Also look if the shift is ‘forward rolling’ or not. Fatigue is a very specialist area. I ask for help after the basics. Medicine is complex, tiring, difficult, challenging and us HF sleep specialists are few and far between and, in general, there has not been much done about understanding fatigue in the area of medicine (sorry). If you are an expert in this area – please, please, forgive the oversimplification. Summary HFs in the first sense is a study of basic processes. Investigations are always about these basic processes – seldom about how someone felt about someone else and about how these senses interacted with the environment, the equipment and the system or method of working. The downside of HF methods – more later in the 'how to do science' blog – is that many say it is eye wateringly expensive. Well, given the potential cost saving, it’s a bargain and research throughout Europe shows that it’s the most effective cost-saving intervention you can do. Research is done in situ and this takes time. The science types get involved to understand the human, the way of working, the equipment and the environment. Thinking of my recent projects concerning firearms deployment – well first get body armour, then training (pick up weapon – ask which end goes bang), then highly supervised patrols … then data collection – assuming your security clearances are all up to date. In respect of medicine, infection control training, theatre training, basic methods training in orthopaedics, come look how the saw has gone through the bone Martin… data collection. In heavy rail – well a lot more – apparently, I’m a great driver – stopping is my only problem! The point is to avoid anyone who says they can do it without the knowledge of the environment or say they developed this measurement tool in nuclear plant operations, and it will work here. The basic human processes described above are the same – but the environment is damned important. This is why a medically trained person is vital to keep the HFs person on a tight bit of rope. HFs is about understanding the limits of the cave dweller who dresses in scrubs and says trust me I’m an DPhil rather than trust me I’m an MD. Next time some slightly higher cognitive processes – memory, search, reasoning, biases heuristics. Thinking and deciding. The good news is that you will have concluded humans should not practice medicine – so how well humans’ reason or don’t will be of no surprise. Happy new year to our reader. Read Martin's other blogs Why investigate? Part 1 Why investigate? Part 2: Where do facts come from (mummy)? Who should investigate? Part 3 When to investigate? Part 5 How or why. Part 6

Consuming tea and cake as I write this also means I can break my ‘in healthcare rule’. This rule says never say to a medical type, “well in other industries it’s done like this”. Healthcare is very different to anything else and outsiders like me should not point at other industries and say there is a panacea of methods that healthcare should use. But, placing the cup down, deep breath – what I discuss here is based on my training in incident investigation in the police (UK, US, and EU), military operations, rail, marine, aviation and security failure. Overall, I’m starting with how I was trained in road death investigation methods and the senior investigating officer (SIO) murder investigation system. Two reasons for this – one, there are online manuals, two, they kind of work and are a good starting point. There is a very big ‘however’ as medicine is different (in fact all industries are different to policing). This, however, is big and came to me as a conclusion while interviewing potential applications for those applying to be investigators in rail. I did not notice, but the rest of the panel noted with some extreme words, that all the police trained investigators were there to try and convict someone rather than stop it occurring again. These blogs are not about criminal and civil liability – just prevention. Super, all police colleagues alienated! Given the ‘Who’ might be one person, let’s think about them and see if we can think about getting a little help to get a team together. Yes, it’s true one nurse will have many investigations to do, but in part two of this series I described that ‘making facts’ is better with two. When I arrive at a crash scene or an investigation, I always ask one question: “Am I the right person to do this?” It’s a bit of a chicken and egg question as you have very little detail. Most of my callouts start with the phrase “you would not believe this but”. The first phase is to take a blank sheet of paper – never a proforma as that will get you only collecting data you expect to find and be a traditional scientist. Start by looking at the scene and thinking about all the possible reasons it could have occurred. Ideally (more in the ‘When’ section), its within 24 hours and nothing has moved or changed – but its healthcare so its weeks later, and the ward has changed from neonatal to geriatric, or the theatre has been moved to the next room. Before you decide who should be on the team, you should first ascertain the likely proximate (main) cause, these are: the ‘environment’, the ‘human’, the ‘equipment or system’. Of course, these factors interact but the proximate cause should decide where to start. Equipment Equipment failure – or the conclusion it’s not usable – is best done with an engineer and a human factors person. Medical equipment is often poorly designed. Why a piece of equipment ‘failed’ in terms of not diagnosing the patient’s condition or keeping them safe is a little complex. In the next post on human factors we shall explore the sub disciplines of human factors and as we shall see there are two groups who specialise in computers (screens etc) and machine design. Now four areas of failure need to be thought about. The machine failed and, for example, its electronics or pump stopped. An engineer is the best person to consult, but how the failure was signalled to the operator is of interest to the human factors person. The machine failed in the sense the operator did not understand how to use it or the output was confusing. The equipment failed in the sense that it looked similar to other equipment on the ward or the theatre but operates in a different way. Sometimes on the same ward machines that have the same function work in different ways. The machine worked well, but its outputs were not immediately comprehendible, or other machines provide outputs in a different way. An example of a simple bit of kit that fails in different ways: A hospital trolley with no locking mechanism on the wheels – it fails as the team chase it round the ward. A hospital trolley that has different drawers on each model so, in an emergency, drawers have to be searched through. A trolley in the north end of the ward which looks the same as other trolleys but is not stocked with the same drugs. A trolley with electronics of a similar appearance to others but where it has different user interfaces and graphical interfaces. I use these examples from my own research. One trust had 17(+) different types of trolley at one site, all with unique set ups and contents, yet all were labelled as having the same function. The experimental test was the question “In what drawer is the adrenalin?” A 100% failure rate was found. More when we talk about human factors. And thanks to Emma for pointing out this major issue – yay for reviewers! Environment People who know the environment best are those who work in it. Typically, the environmental issues to measure and understand relate to lighting, stressors like heat and cold, ergonomic physical space and, in my experience, noise levels. In many other industries a noise level of 120dB means closure of the site and ear defenders, in healthcare a noise level typically found in a factory is ignored. In the forthcoming human factors posts I’ll cover sound. Environmental factors are not as easy to correct. Telling the hospital that the anaesthetics room is so small it can’t be used will cause death threats from the facilities management team! Lighting changes – from fluorescent or incandescent to LED always causes issues. However, the issues of lighting – and by implication colour rendition – can all be simply measured by tools in the typical human factor types backpack (designer of course). Light meter, dB meter etc. Human factor people should be able to chat about the physical layout and how the fact us slowly evolving cave dwellers are physically weak should be discussed. Sometimes the physical design of an environment is very poor. I’ve heard the comment “With one hand the operator controls this, with the other these controls, and the other hand interacts with the screens”. Human 95% is the number you should be familiar with. That to say the most common factor – or contributory factor – is the human element. Research from the late Barbara Sabey’s seminal work points out that in 95% of cases it is the human that’s caused the problem. Irrespective of industry, location or activity that number (or very close to it) comes up. So, a human factors person should be part of the team. It takes a postgraduate qualification and lots of experience so hire one early on. They do drink lots of tea and although they are doing 95% of the work – they are only one of your team. Systems It’s true I should say it’s a human factors person that does this bit, but nurses are the best I’ve found. By the phrase ‘system’ we mean in terms of system theory, which 'Professor' Wikipedia says is “Systems theory is the interdisciplinary study of systems. A system is a cohesive conglomeration of interrelated and interdependent parts that is either natural or man-made. Every system is delineated by its spatial and temporal boundaries, surrounded and influenced by its environment, described by its structure and purpose or nature and expressed in its functioning. In terms of its effects, a system can be more than the sum of its parts if it expresses synergy or emergent behaviour.” I should describe psychology systems theory (part of human factors) – but the above is good enough for now and there are many sub fields. In essence, look at how information flows and how many stages people need to go through to achieve a task. Each stage or function adds another source of error. Walk through the process and critically examine how each stage can fail. My work in the military tells me every stage that can fail will. Remember humans are fallible and the system or method of working should fail-to-safe. Some within the NHS say fail to safe is a new concept. It’s part of the 1832 Railways act. If we mention a system it might be worth saying the phrase – task analysis. Task analysis is something human factors types are trained to do. It breaks down a task or system into each of its constitute part and looks at the order or dependencies that are needed to complete each main and sub task. The classic training is making a cup of tea, the victim, I mean student, lists all the stages and the master (teacher) points out that there are lots more stages. The student says fill cup with hot water. The master says – but where does the cup come from? Student and teacher hate each other for years after but a list of things to do to achieve the task is formalised. It’s a useful tool but often it’s the most junior member of an human factors team that does it and it’s a rite of passage to say you are a human factors person. The method should be used to help the investigation. Buy me a drink and I’ll explain why the doors of a tram – when its coupled to another tram, and that tram is in a certain station, and the third emergency button in carriage one is pressed while the driver is closing the doors in carriage two while another part of the tram the smoke detector is activated within 0.25 of a second of another alarm… well you get the picture. Four in a team then? With four headings this kind of implies four people in the team. The team should have those skills but what about the personal qualities and above all the relationship to the injured party. The investigation teams need to be independent and not be familiar with anyone involved. Humans are not rational data collecting machines and knowledge about others and the environment will cloud how you collect the facts – even if you try hard. The ideal lead investigator knows perhaps a little about the hospital or care place but does not know those involved. They should know a little about the equipment or machines, but not be so familiar that they know the ‘work arounds’ to get it to function. The lead investigator should handle discussions with outside organisations. Now if you are following carefully you note I’ve just added another team member – the senior investigator or lead investigator. This person organises the team of those with different skills and is responsible for the output and keeping the team from the pressures of the outside world, far enough away so the team can collect data. They should be cognisant of not just the investigation team but also those who were involved in the incident. This is where healthcare is very different to any other industry – the care of those involved. Care of those involved is, in my experience, very strange in healthcare. If you attend an incident you ensure that all those involved get home safely and have a contact point. In healthcare the fact that it’s highly unlikely that the action that led to a fatality was deliberate and the nurse, doctor, administration person was not trying their best appears to be overlooked. I attended an incident where the team were in tears and visibly shaking, they were told to drive home and come back tomorrow (next shift and list already given to them). It should not be the role of the investigator to organise a taxi and lend a phone so family can be called for support. Now the ‘Who’ may suddenly, radically change. The question first in your mind should be – is this an accident? You may recall in part one – ‘why investigate’ we defined an accident or incident. Essentially, we decided together that it’s a random rare unforeseen event with lots of variables coming together in one moment in time. Well at this point you should know if it’s ‘accidental’ or deliberate, and if its random or not. The who investigates or leads the investigation could change. If the test of accidental is not met, then it’s a criminal matter and the lead investigator or police senior investigating officer will take over and “Oh well done you are using a recognised method” should be heard. Investigations involve a small team. There is lots of data and the experience of just one person is not enough. A lead investigator can deal with the media, families and ensure the investigation team collects the facts. Those who investigate need to be able to collect the facts needed and be scientific in their approach. The person collecting evidence from, say, CCTV needs to have some experience of using it, and the person considering the medical records needs an understanding of how that particular ward uses the charts. Or, in my experience where they are, which is different to the ward on the floor below. No one has all the experience needed, and we all need to learn. My first recovery of CCTV images took two days. Strange the operator (now manager) and I are still friends many years later, but approach the matter with a smile and a look of “I’m lost”. Time off from the day job is vital. Investigations are hard work and mentally and physically exhausting. How long should the team be together? Well that depends and only comes apparent after a day. I’ve had a purchase order for 6 weeks investigation services and finished at lunchtime on day one. I’ve been asked to spend 6 weeks and then two years later still going. One of my team did the whole thing in 30 minutes… saving the 12 weeks of funding for something else. When I’m part of an investigation team I deal with humans and the systems, I’ve no (well little) knowledge of the engineering side or the other facets. Human factors is part of the story and the skill is for the lead investigator to bring all the views together. A human factors type should not lead the investigation. More colleagues alienated. Summary Investigations should be conducted with a small team. Small teams need a leader and that can be the person who is also charged with the welfare of those involved and the communication with those outside the team. The team should have time enough from their ‘day jobs’ to do it. How long do they need off? Well that’s down to the incident. The best bit of equipment to take is a blank sheet of paper, and there is a vital need to effectively communicate the findings. That’s three blog posts on the investigation method. Still lots to do. Read Martin's other blogs Why investigate? Part 1 Why investigate? Part 2: Where do facts come from (mummy) Human factors – the scientific study of man in her built environment. Part 4 When to investigate. Part 5 How or why. Part 6

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. CCTV 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 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? Conclusion 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 Martin's other blogs Why investigate? Part 1 Who should investigate? Part 3 Human factors – the scientific study of man in her built environment. Part 4 When to investigate? Part 5 How or Why. Part 6

So, why do we investigate? In this part I’ll cover the philosophy of why we do it; later posts aim to provide an understanding of who might be the right person to do it. Having covered the why, I’ll do some posts about the when (always within 24 hours); the who (as in staff rather than the still-touring rock group); the what; and a few practical ‘top tips’ on the how. Why do we investigate? Well investigation gives jobs to us investigators and, well, that concludes my piece. Well let's at least think about the other reasons. Organisations investigate because their regulator or management team want it done. Sometimes investigations are done so the organisation feels good about itself. A report whose measure of impact and success is based on the weight of the printed pages, with a good report being 3–4 cms thick and the ultimate report keeping the door open in the summer, is not uncommon. It may be worth another post about communication of findings to achieve an action. A poster on the wall is not a good idea, or courses on non-technical skills (NTS) or team talks. Organisations often investigate in order to sack someone. Sack someone and the problem has gone. Well, while there is a feeling of action, this means very little learning is done, and from a human factors perspective it’s unlikely the human has done it deliberately. The organisation should really build a system that is tolerant of human error. In aviation, we (my company) were at the forefront of the no blame reporting systems. Protecting the organisations criminal and civil liability is often the reason for undertaking the investigation. Doing an investigation with only this in mind hampers the investigation team. Yes, liability is an issue, but in healthcare there is an overriding duty of honesty and candour. If you investigate knowing the Coroner will ask you awkward questions, this will affect what you investigate. The legal side and compensation are a matter for the lawyers. In my view, your duty is to report what you find. The only reason to investigate is to stop it happening again. In the words of the philosophers – Metallica – nothing else matters (hopefully the reader is cognisant of rock music). The investigation is only there to prevent another incident occurring, by providing evidence, obtained through careful data collection, that means it simply will not occur again. What’s an accident then? I’m now very conscious that we have got ahead of ourselves. We are talking about an investigation of an incident or accident or crash or oversight, but what do we mean by an incident or accidental death etc.? An accident is a typically defined as: ’"an unforeseen rare random event with multiple causes where in one moment in time something went wrong." Let’s take each of those words and consider why we investigate. Unforeseen – if it was expected – then it’s not accidental and most likely the subject of a criminal investigation. Rare – well how many car crashes have you seen? How many planes have crashed while you watched them? How many trains have you travelled on that hit the buffers? Crashes, incidents etc. are thankfully rare. Given what humans are designed to do – hangout and chill on the African Savannah lands – then its amazing how few incidents occur, especially with poor technology and the really badly built environment found in hospitals. I still recall watching an anaesthetist crawling under the patient’s bed as the room was too small to take a bed as well as the team. Random – you should not be able to predict precisely when they will happen. You may say there is an increased risk of an error in the operating theatre if the surgeons have loud rock music (Metallica) playing and the lamina flow is noisy, meaning no one hears the “I’m doing the left side here aren’t I?" But you can’t point at a patient and say they will die at 14:16pm, when we realise we have put the nerve block on the wrong side. Multiple causes – Human factors being a science means sad science types count the number of variables. In road transport back in 1972 (before mobile phones and Bluetooth that will not connect over 60mph – damn it – calm blue ocean) – where was I – oh yes over 1300 variables were identified. Importantly, an incident does not have a single cause but typically 2–4 or so variables come together in a moment in time. Top tip – if anyone says an incident has one cause then smile and walk away. Moment in time – A split second later the train driver would have seen the red signal because the train spotter in the way would have leaned over a bit further. A millisecond earlier the scrub nurse would have noticed the tray was not on the trolley before her colleague distracted her with a question about the x-ray. Time is the essence. When investigating an incident, you have lots of time, the incident occurred in a millisecond. Investigation therefore looks at a rare random event with the potential to have been caused by a complex failure in systems, equipment, human and environmental factors. Later in the series I’ll explain these factors in more detail. How do I know that I have investigated an incident to allow prevention to occur? Revisit the scenario and see if it could occur again. In one investigation that we did we found that a patient reporting in the emergency department and requiring a chat with a neurologist took 70 steps or stages in the booking process. This included a message to a fax machine whose location was a mystery. Yes, deep breath, an error model means a near perfect failure rate and no fail-to-safe method (our investigation and remedy designed a system of just one stage – no possible error and even designed a leaflet about the patient not driving home afterwards). The simple test is to go into the Emergency Department in the role of a ‘patient’ who needs to speak to a neurologist and ask the team to walk you through their processes. True in this retest there were now two stages – but the system failed to safe, and the ED team remembered I like tea. If you do an investigation and a year later the incident could still occur, and nothing has changed, then you have wasted your time. Importantly – say this is so to whoever will listen. As an investigator you sometimes need to spell things phone-net-ic-ally, so people understand that you will not go away and that sacking someone was not the answer. Ok, it maybe you that’s then sacked for asking a question phone-net-ic-ally... We have covered why we investigate and what an incident is. There is a long way to go before we reach the nirvana of incident free hospitals – but we have made a start. Well not really, it’s time to conclude with a confession. There is another reason why I investigate crashes/incidents, have done all that training, wear scrubs, body armour, get cold wet and damp (not at the same time hopefully). The other and for me main reason to investigate a fatality is to tell the family why their loved one died. It’s a privilege to explain why we think it occurred and give some reassurance that it will not occur again. I do investigations where police officers have died. I never expect the family to agree with me, but only to listen to what I have found. Sometimes after an investigation the family may come with us as we do experiments and be part of the world of science. It’s true they may cry and get emotional – but they are only doing in public what we do ourselves in private. Read Martin's other blogs Why investigate? Part 2: Where do facts come from (mummy)? Who should investigate? Part 3 Human factors – the scientific study of man in her built environment. Part 4 When to investigate? Part 5. How or Why. 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