HF in Diving for Dummies: Part 1: Human Factors

- english gareth lock human factors non-technical skills Jul 30, 2022

This is a 10-part series of blogs that will be published once a fortnight to bring the basics about human factors in diving to the fore. They won’t be long, they won’t have lots of jargon in them, and they will have a case study or series of examples to bring the theory to life.

The reason for this series is that I listen to the feedback I get like "While the information you post is useful, it can come across as well above the level of the average diver, as such, the message isn’t getting across." As we’ll see in the communication blog, if A is communicating to B (or lots of Bs), and B doesn’t understand, then the responsibility for changing the message so that B can understand it belongs to A. B needs to say they didn’t understand and that has happened because I have had this feedback.

The first blog will be about Human Factors, what they are, what they aren’t and why you should care. 


Human Factors

Human factors is the science which looks at the interactions between humans (individually, and as a team member), their equipment, the environment they are in, and processes/procedures. More simply, human factors is about making it easier to do the right thing, and harder to do the wrong thing. That ‘thing’ might be one of the numerous activities or pieces of equipment or manuals/processes we interact with when we go diving.

  • How you give a dive brief so the team or students understand the task ahead and you can check their understanding to ensure your message has been understood. (Communications. Leadership and Followership. Teamwork).
  • How you design a pre-dive checklist so that it flows well and how you create a supportive social environment so that when it is read out, those who are subject to the checklist provide the correct responses and everyone involved doesn’t just pay lip service to the checks. (User interface. Decision Making. Teamwork. Communications).
  • How you make decisions when you are dealing with unknowns and assumptions so that you are more likely to make a ‘correct’ decision. (Decision Making. Situation Awareness).
  • How to remember critical items of equipment or a process that needs to be followed. (Decision Making. Situation Awareness).
  • How you lead a dive team on a project or an expedition or a team of students on a dive class, so that the team do what is needed of them because they ‘want to’, not because they ‘have to’. (Leadership. Followerships. Communication. Psychological Safety.) 
  • How you interact with your dive computer or CCR controller so your selections are easy and intuitive and you don’t get frustrated when it does something you weren’t expecting. “What’s it doing now?!!” (Decision Making. Situation Awareness.)
  • How to examine a diving incident or near-miss with a view to learning from it, rather than focusing on individual ‘human error’ and apportioning blame. (Just Culture. Non-Technical Skills. Psychological Safety.)

One of the biggest ‘problems’ with human factors is that it is general in nature and specific in application. What this means is that in general, people behave in a predictable way given certain conditions in which they are placed. Ironically, this predictable behaviour might be irrational! It made sense to them at the time but doesn’t make sense afterwards because it was ‘obvious’ that it would end up going wrong. It is only obvious and ‘certain’ after the event.


General in Nature. Specific in Application.

This ‘general nature’ means that human factors is often dismissed as ‘common sense’ or just ‘something that humans do’, and yet when we dig into the specifics of the issue like how miscommunication developed such that a diver got separated on a reef dive, or why a diver entered a wreck without training and subsequently drowned, or why an instructor taught a CESA which then breached standards, we can see that there were specific things to be aware of.

Therefore, to really understand and apply human factors concepts, we have to look at each individual case/situation with a fresh set of eyes, so that we can understand the context. This takes a level of commitment that many aren’t willing to apply. Ironically, this non-committed behaviour is a recognised general behaviour! We don’t like change, especially if nothing has gone wrong in the past! So we have to understand the specific issues why learning isn’t happening.

Human factors is also not crew resource management or non-technical skills. These terms will be explained in more detail in the next blog in a fortnight’s time, but they are a subset of human factors.


This is an example of a user interface design issue - a key part of human factors design and implementation. In this case, the power adaptor port and gas inlet for the trimix analyser are almost identical in size and shape and because there isn't any labelling on the analyser, it isn't easy to work out where the gas analysis tube goes. If you've got the instructions, you can read them, but who takes the instructions with you to a dive site. You might know, but what happens when you hand your analyser to a friend so they can analyse their gas. If you trying to analyse 21/35, the gas feed will draw in air, measure the O2 as 20.9 but there will be no helium showing in the mix because the hose is connected to the power port.

This might appear 'obvious' after the event, but think about how it makes sense for the user. Designers need to take into account how someone might use their devices/processes/programmes incorrectly because they don't have the designers knowledge and base assumptions.



Human factors is about making it easier to do the right thing, and harder to do the wrong thing. This could be about decision making, situation awareness, communication, leadership, teamwork, equipment design, checklist design, class dynamics, debriefing or incident investigation. To be effective, it has to be applied to the specific activity or situation, rather than be dismissed as ‘common sense’ or ‘that’s obvious’.


Further Reading:

Humanistic Systems: Four Kinds of ‘Human Factors’ - https://humanisticsystems.com/2017/08/11/four-kinds-of-human-factors-1-the-human-factor/   


Gareth Lock is the owner of The Human Diver, a niche company focused on educating and developing divers, instructors and related teams to be high-performing. If you'd like to deepen your diving experience, consider taking the online introduction course which will change your attitude towards diving because safety is your perception, visit the website.