To Err is Human – Human Reliability Analysis

(This post is part of the 31010 Series of posts on Risks & Ventures. For more information on this series please follow this link).

As the early 18th Century English poet Alexander Pope wrote, “to err is human”, and in risk management it is accepted that any process that involves human action has a possibility of error.

Of course, the likelihood of a human making a mistake is going to depend on a lot on what you are expecting that human to do, as well as how well they have been trained to do it, and how motivated and how distracted they are too, amongst other factors. However even in situations where people are allowed to focus, have been trained well and are appropriately motivated errors still creep in. 

Think, for example, if you have ever watched a player in any sport have an absolutely perfect game or tournament, even at the highest levels?

If you are a regular sports fan you might be able to name a few occasions where someone has performed very close to perfectly in a particular game or tournament, or maybe even scored the best possible score in a sport where the scoring system allows a “perfect” performance, like the famous 10 point performance in gymnastics. However the fact that you can actually remember these specific, outstanding performances out of all the sport you have watched shows how rare they are, and how common errors are too, even amongst very well trained, focused and motivated people.

In formal risk management one term used to describe human errors is human factors. This seems, so far as our own understanding of it goes, to have originated in the field of ergonomics with the idea that processes, systems and equipment should be designed to be more functional and safer for humans; however in many industries the term has become a bit of a catch-all term for something that occurs or could happen based on human behaviours and humans making a mistake. (1)

Human reliability analysis isn’t a single risk assessment technique like some of the others we have looked so far in this series of posts in Risks & Ventures instead it is more of process, which when followed will help evaluate how likely human errors are and what can be done to avoid them.

It goes something like this:

Step 1 –  Analyze the activity

A task, process or activity is broken down into specific steps and where necessary sub-steps, and each step is then analysed for ways in which a human could get it wrong. It’s important to be highly methodical while you are doing to his to make sure you don’t miss anything out.

Let’s imagine that it’s a bit like you are creating a recipe that someone has got to follow. It might be a complicated recipe with technical terminology that only someone who that a confidant and knowledgeable chef (or practitioner of the activity) can follow, or it might be something that anyone with some rudimentary knowledge ought to be able to manage. Either way at every step you have make sure that you aren’t asking someone to do something that is beyond their capabilities.  

It’s also highly recommended to get your ‘recipe’ or steps down in a written form as you are doing it whether on paper, whiteboard or electronically.

Step 2 – Analyze why the errors could happen

In places where potential human errors have been noted, consider what the causes of these errors are going to be.

So if we talking about the process of crossing a road, one of the main causes of errors is going to be pedestrian or driver distraction. Or if a process involves entering a PIN code one human factor is that someone might forget it, another is that they might not know in the first place because another human never told them they needed it. 

You also have to think about the person, the things that could influence them and the situation and environment too.

Maybe a certain activity is really easy to do outside in daylight but harder when it’s darker, like playing sports if you didn’t have lighting. Maybe a process is simple when you just have to do it once, but then having to do it repeatedly under time pressure during a long shift the likelihood of errors goes way up. 

The things that could influence how well an activity is performed are called Probability Shaping Factors, and in formal risk management we might try and take another step with these factors by trying to figure out how likely each of these factors.

In other words if we have identified that someone becoming tired is a going to be a factor that causes errors, we need to ask how likely is it that this human doing it is going to be tired. If they work short shifts with good breaks we can estimate that they probably should be low, on the whole, but it they are required to work long shifts with minimal breaks we can make a reasonable estimate that this is much more likely to become a relevant factor. 

This applies to the environment in which the activity is being performed too, so if you have a task to load equipment into vehicles in a warehouse yard you might be much more likely to make a mistake if it is dark than in the daylight. But if the yard only opens at 9am and shuts down at 4.30pm then in most places in the world you are not ever going to be doing this activity in dark so it’s not a relevant factor, or a much less relevant one than many others.  

This can get quite technical, and in formal risk management businesses may use databases of statistics to help them understand how different factors should be weighted, and they will also  ask subject matter experts too but the key principle that anyone can apply is trying to understand which factors are more likely than others, and then making sure your analysis takes account of this the best that you can, with the resources and time you have available to do the analysis. 

Of course risk management isn’t just about preventing undesirable things happening but also trying to find ways to secure opportunities, and although Human Reliability Analysis emerged first as technique to look at why things might fail, it’s totally possible to also use the same concept and process to look at factors which might improve success too. 

When can I use HRA?

HRA is most useful when for 1. analysing where errors could occur in a process or activity, 2. identifying why these might occur, and 3. for trying to improve processes.  It’s quite complementary to techniques like Bow-Tie Analysis and Structured What-If Thinking.  

HRA is probably best suited to situations where activities are quite same-y or routine, where it is easier to predict the types of activities and mistakes that could realistically occur. As with many (most) other risk management techniques it is only as good as its inputs, so the more information there is available about the activity and the associated probability shaping factors usually so much the better. The more complex or unique a situation is, the more difficult it will be to analyse because the range of possible human behaviours and types of errors will increase too. 

Good HRA ideally also should consider psychology and cognitive functions (i.e. how our brain and minds work), as well as physiology if we are talking about a process that involves physical activity too.

Practical Human Reliability Analysis

HRA can be applied in a quick, practical way in day-to-day life too, because even just doing a short-form version where you quickly but logically have to think through and map out a pathway toward a particular objective while considering where human errors could occur – yours or someone else’s – is actually a pretty good way to make a success of it of that objective.

Like many of ISO 31000’s formal risk management processes and risk assessment techniques, Human Reliability Analysis needs to be done with the resources that you have available, so it you have weeks to do an assessment, with large amounts of supporting data, subject matter expertise and the ability to even conduct trials to see where errors are most likely that is obviously ideal; however if all you have is a few minutes to think about what you are doing and the potential mistakes the concept is scalable to be able to add some value in those circumstances too. 

Even simpler than that, just understanding and always remembering that humans, even the good, knowledgeable, intelligent and reliable ones, will always sometimes make mistakes is a good message to takeaway and apply when you are planning anything. 



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