What Human Factors Isn’t: 4. A Cause of Accidents

‘Human Factors’ (or Ergonomics) is often presented as something that it’s not, or as something that is only a small part of the whole. Rather than just explain what Human Factors is, in this sporadic series of short posts I will explain what it isn’t. The posts outline a number of myths, misunderstandings, and false equivalencies.

In this series:

  1. What Human Factors isn’t: 1. Common Sense
  2. What Human Factors isn’t: 2. Courtesy and Civility at Work
  3. What Human Factors isn’t: 3. Off-the-shelf Behaviour Modification Training
  4. What Human Factors isn’t: 4. A Cause of Accidents (this post)
Royal Navy Media Archive CC BY-NC 2.0 https://flic.kr/p/NqZrz5

Human Factors Isn’t a Cause of Accidents

An unfortunate use of the term ‘human factors’ in industry, and in the media, is as an explanation for failure. Through this lens, human factors is (or ‘are’, since the phrase tends to be used as a plural in this context) seen as a cause of accidents or other unwanted events. This immediately confuses the discipline and profession of Human Factors with a narrow, unsystemic view of factors of humans – human factors in the vernacular. (Much as I dislike capitalisation, I will use it here to separate the two.) While human limitations are relevant to accident analysis (and the analysis of work more generally), and indeed form part of many analytical methods, neither the vernacular ‘human factors’ nor the discipline of Human Factors is an explanation for failure. Below, I outline a few problems with this all-too-common perspective.

‘Failure’ means not achieving planned objectives. Since people set objectives, make plans and execute actions to achieve objectives, then almost all failure is associated with humans, unless there is some chance agency or natural phenomena involved (e.g., weather). Even then, one could take a counter-factual perspective, as is often done in accident analysis, and say that humans could have or should have predicted and planned for this.

Logically, ‘success’ has the same characteristics. Humans set objectives, make plans, and execute actions at all levels of system functioning, from law-making to front-line performance. So if failure is down to ‘human factors’ then so is success, which arguably accounts for the majority of outcomes in day-to-day work.

By this reasoning, ‘human factors’ as a cause of accidents is a monolithic explanation – even more so than ‘safety culture’. ‘Human factors’ as a cause of accidents explains both everything and nothing. Having said this, ‘human factors’ is often seen more specifically as a set of factors of humans (humans being unreliable and unpredictable elements of an otherwise well-designed and well-managed system) that are proximal to accidents.

This interpretation has been reinforced by the use of the word ‘organisational’ alongside ‘human’ in some quarters. For instance, the UK Health and Safety Executive used the term ‘Human and Organisational Factors‘ to broaden out the perceived scope of the ‘HOF’ contribution (to incidents and accidents), and there is a growing ‘Human and Organisational Performance’ movement, which has grown from ‘Human Performance‘. This is curious to many Human Factors professionals, because organisations – being created by, comprised of, and run by humans – were always within the scope of Human Factors (sometimes called ‘macro ergonomics‘) from the beginning.

The proximalisation and narrowing of ‘human factors’ becomes especially important with the post hoc ergo propter hoc fallacy, that because an event happened after something (an action or omission) then it happened because of that something. This is especially problematic in complex, high-hazard systems that are highly regulated and where systems are required to account for performance variability, in terms of design, management, and operation.

An example of proximalisation can be seen in the aftermath of the train that crashed at Santiago de Compostela in July 2013. Human error was immediately reported as the cause. A safety investigation by CIAF (here in Spanish), published in June 2014, found that driving staff failed to follow the regulations contained in the train timetable and the route plan”. Subsequently, the European Railway Agency (now the European Union Agency for Railways) found that the emphasis of the CIAF report is put on the direct cause (one human error) and on the driver’s (non-) compliance with rules, rather [than] on the underlying and root causes. Those causes are not reported as part of the conclusions of the report and typically are the most likely to include the organisational actions of Adif and Renfe.” As reported here, “many survivors, campaigners and rail analysts…questioned why rail officers in charge of the train and rail network had not factored in the possibility of human error – particularly at a bend as potentially dangerous as the Angrois curve – and had failed to put in place technology that could mitigate it”.

The safety investigation seemed to mirror a view of causation that allows for counterfactual reasoning only in the proximate sense – who touched it or failed to touch it last. In this case, and many others, it seemed that omissions are only causal when they occur at the sharp-end, even though sharp-end omissions typically occur over the course of seconds and minutes, not months and years.

In the case of Santiago de Compostela, the driver Francisco José Garzón Amo was the only person facing trial for much of the time since July 2013. However, several officials have been named in, and dropped from, judicial proceedings over the years. Their causal contributions seem to be harder to ascertain. At the time of writing, Adrés María Cortabitarte López, Director of Traffic Safety of ADIF, is also facing charges for disconnecting the ERTMS (European Railway Traffic Management System) without having previously assessed the risk to make that decision. (Ignacio Jorge Iglesias Díaz, director of the Laboratory of Railway Interoperability of Cedex said that ERTMS has a failure every billion hours, while part of the security provided by the ASFA system “rests on the human factor”.) As yet, over seven years later, there is no date set for the oral trial to find out if the accused are finally convicted of eighty crimes of involuntary manslaughter and 144 crimes of serious professional imprudence.

All of this is to say that there are consequences for both safety and justice of the framing of ‘human factors’ as a cause of accidents, and the scope of ‘human factors’ that is expressed or implied in discourse also has consequences. By framing people as the unreliable components of an otherwise well-designed and well-managed system, ‘human factors as a cause of accidents’ encourages brittle strategies in response to design problems – reminders, re-training, more procedures. But this is not all. This perspective, focusing on ‘human factors’ as the source of failure, but not the overwhelming source of success, encourages technological solutionism – more automation. This changes the nature of human involvement, rather than ‘reducing the human factor‘, and comes with ironies that are even less well understood.

So ‘human factors’ isn’t an explanation, but Human Factors theory and method can help to explain failure, and moreover, everyday work. Human factors isn’t a reason for failure, but Human Factors helps to reason about failure and – moreover – about everyday work.

Unfortunately, some Human Factors methods that have emerged from a Safety-I mindset (curiously different to the progressive mindset that created the discipline) may have encouraged a negative frame of understanding. The Human Factors Analysis and Classification System (HFACS), for instance, classifies accidents according to ‘unsafe acts’ (errors and violations), ‘preconditions for unsafe acts’, ‘unsafe supervision’, and ‘organizational influences’. The word ‘unsafe’ here is driven by outcome and hindsight biases. Arguably, it should not be attached to other words, since safety in complex sociotechnical systems is emergent, not resultant. Such Human Factors analysis tools typically classify ‘error’ (difficult as it is, to define) and ‘violation’ only at the sharp end (blunt end equivalents are seen as ‘performance shaping factors’ or in the case of HFACS – influences). So, inadvertently, Safety-I Human Factors may have encouraged proximalisation to some degree, linguistically and analytically, since errors are only errors when they can be conveniently bound, and everything else is a condition or influence – ever weakening with more time and distance from the outcomes. Again, this has implications for explanation and intervention.

Still, in the main, Human Factors is interested primarily in normal work, and sociotechnical system interaction is the primary focus of study, not accidents. Within this frame is the total influence of human involvement on system performance, and the effects of system performance on human wellbeing. Even within safety research and practice, there is an increasing emphasis in Human Factors on human involvement in how things go right, or just how things go – Safety-II.

But the term ‘human factors’ will probably be used in the vernacular for some time yet. My best advice for those who use the term ‘human factors’ in their work is to think very carefully before using the term as a cause of, or explanation for, failure. Doing so is not only meaningless, but has potential consequences for safety and justice, and even the future of work, which may be hard to imagine.

Author: stevenshorrock

This blog is written by Dr Steven Shorrock. I am interdisciplinary humanistic, systems and design practitioner interested in human work from multiple perspectives. My main interest is human and system behaviour, mostly in the context of safety-related organisations. I am a Chartered Ergonomist and Human Factors Specialist with the CIEHF and a Chartered Psychologist with the British Psychological Society. I currently work as a human factors and safety specialist in air traffic control in Europe. I am also Adjunct Associate Professor at University of the Sunshine Coast, Centre for Human Factors & Sociotechnical Systems. I blog in a personal capacity. Views expressed here are mine and not those of any affiliated organisation, unless stated otherwise. You can find me on twitter at @stevenshorrock or email contact[at]humanisticsystems[dot]com.

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