Introduction to Human Factors: What, Why, How?

What is Human Factors?

It’s about the Human - that’s all of us – and Factors that influence how we operate in the world. These factors cover a wide range, from our own experience through to the design of equipment or presentation of information, to the effects of budget cutbacks and the influence of safety culture. It’s about understanding and improving how we interact with people, processes, products and places to make us more efficient, comfortable, healthy and safe.

Within the workplace, Human Factors is concerned with designing systems of work to support people in their work, rather than designing systems to which people must adapt. Human Factors is a scientific discipline that takes account of human abilities and limitations – it is about understanding such capabilities and limitations and designing the system of work with that in mind.

A simple way to view Human Factors is to think about three aspects: the job, the individual and the organisation and how they impact on people’s health and safety-related behaviour.


Job-related factors include procedures and workload. Individual factors include competence and fatigue. Organisational factors include safety culture and safety critical communications. These factors all influence performance at work and are often referred to as performance influencing factors (PIFs). The Human Factors topics here focus more on the cognitive and organisational aspects of Human Factors. The HSA already has guidance and supports relating to physical ergonomics and psychosocial hazards including work-related stress and bullying.

Why Human Factors?

Adopting a Human Factors approach to health and safety management recognises the contribution people make in the workplace. The variation, adaptability and innovation inherent in the decisions and actions taken by people at work every day enable them to carry out their tasks and promote system resilience. The ability of people to adapt to changing circumstances at work is more often a source of task ‘success’ rather than task ‘failure’ – competence is a key factor to ensure people make decisions and take actions within the boundaries of safety.

The Human Factors approach not only reduces operational risk from human error, it also improves overall health and safety performance. It promotes workforce effectiveness through understanding inter-related workplace factors and helps to optimise decision making and a positive health and safety culture, bringing performance and business benefits.

How we all work

We all make decisions and take actions at work that make sense to us at that specific time and in that particular circumstance. Our decisions and actions will depend on our knowledge, our skills, our experience, the information available to us, the focus of our attention and our goals at that time.

We all make errors and break rules no matter how well trained, experienced and motivated we are to do something right. Whilst human error can directly cause an accident, people tend not to make an error deliberately.  Human error is normal and predictable. As stated in the Health and Safety Executive guidance on ‘Reducing Error and Influencing Behaviour (HSG48, HSE, 1999)’,:

“We are often ‘set up to fail’ by the way our brain processes information, by our training, through the design of equipment and procedures and even through the culture of the organisation we work for. People can make disastrous decisions even when they are aware of the risks. We can also misinterpret a situation and act inappropriately as a result.”

Taking a reading from a wrong instrument, driving a road tanker off while the hose is still connected or relying on an out-of-date diagram during maintenance – these are all examples of errors that can happen in the workplace. To prevent errors recurring, it is important to understand what it was in the system of work which caused or helped to cause the error. Was it a distraction or something else that led someone to have the wrong information, or something which gave them the wrong priorities?

So, while it is reasonable to expect people to ‘do their best’ at work, relying on this vague aspiration alone is not enough to control risks.

Human Factors and Risk Assessment

Human Factors approaches are based on workforce engagement - having conversations in the workplace on the factors that influence how people work. This not only reduces the probability of things going wrong, but also enables people to work more effectively and efficiently. Risk assessment is an opportunity to facilitate meaningful conversation with workers about what can go wrong ahead of time. Identifying what can go wrong in risk assessment means that systems can be put in place ahead of time to minimise the potential for workplace accidents or ill-health.

A structured and systematic approach to identifying and managing error as part of risk assessment ensures the potential for accidents can be reduced and mitigated. When conducting a risk assessment, the person is the central focus: consider tasks where there is a reliance on people taking action, making decisions and communicating. It is important to consider the following three elements and how they interact:

  • who is doing the task - the employees and their characteristics, tenure, training, expertise and workload;
  • what people are doing - the task and its start point, end point, machinery or equipment used, procedures in place and;
  • where people are doing it - the physical environment e.g. light, heat, noise, space, and the organisation or the broader social environment.

Where there is a reliance on people, talk to them to consider the following in your risk assessment:

  • what can go wrong when people are doing this task?
  • what are the health and safety consequences of things going wrong?
  • what makes error more likely?
  • what control measures are needed?
  • what support is required to do the task safely?

The aim of engaging your workers in talking about workplace activities is to find out what actually happens when a particular job or activity takes place and not what should happen. By talking through a job or activity, you can identify problems that need attention and incorporate this understanding into your risk assessment.