The Health and Safety Executive’s guidance HSG48: Reducing error and influencing behaviour offers a structured approach to understanding how wider organisational, task and environmental conditions shape human performance in the workplace.
This guide explores how HSG48 supports meaningful accident and incident investigation outcomes, how human factors analysis leads to stronger risk controls, and how adopting this approach builds a safer, more resilient working environment.
What is HSG48?
HSG48: Reducing error and influencing behaviour sets out how human factors influence health and safety outcomes. Human factors, in this context, refers to the way people interact with tasks, tools, work systems, and the organisation around them.
Rather than viewing error as a personal failing, the guidance emphasises that incidents are usually shaped by the surrounding conditions – the adequacy of information, the pressure placed on individuals, the design of the task, and the cultural expectations within the workplace.
The guidance encourages organisations to look beyond “what someone did” and examine “what allowed that behaviour to make sense at the time”. When investigations take this wider, contextual view, the focus shifts from fault-finding to identifying system improvements.
HSG48 sits alongside other HSE human factors guidance, such as HSG65 (Managing for Health and Safety), and forms a core part of the HSE’s wider position that organisational design influences safety as much as individual capability.
Why are human factors important in investigations?
Applying human factors during an accident or incident investigation changes how the process is carried out in practice. Investigators examine the wider conditions that shaped decisions and performance at the time.
Understanding how the task is performed
Human factors investigation involves looking at “work-as-done” rather than “work-as-imagined”. That means observing the task, reviewing how it is normally carried out day-to-day, and comparing that to documented procedures.
If frontline practice has diverged from written instructions, there is usually a reason (for example, the procedure may be impractical, outdated, or incomplete). This insight enables organisations to see where systems are not operating as intended.
Examining environmental and operational influences
Investigators consider elements such as workload peaks, fatigue, interruptions, layout, equipment placement, tools available, and the amount of information a person had access to at the time. These factors may create conditions where risk increases even when employees are trying to work safely. Human factors help identify these conditions so they can be improved.
Speaking to those involved across the system
Rather than interviewing a single individual, a human factors approach involves speaking with others who were working within or interacting with the same system. This wider perspective shows how pressures, expectations, and constraints were experienced more broadly, and whether the conditions that shaped the error were unique or systemic.
Mapping normal work, not just the event
Human factors investigation examines how the task is normally carried out day-to-day.
Investigators compare the incident against routine work practices to determine whether the event was a one-off deviation or part of an established pattern of informal shortcuts, undocumented work methods, or tolerated risk-taking. This helps identify whether the organisation has been relying on good fortune rather than robust system design to keep people safe.
How does HSG48 support accident prevention?
By focusing on the conditions in which work takes place, HSG48 enables investigators to identify which system improvements will effectively reduce the likelihood of repeat harm.
Analysis is more likely to uncover systemic improvement areas such as:
- Unclear procedures. Instructions may not reflect how the task is carried out, or they may be overly complex, hidden in multiple locations, or not written with the end-user in mind. Updating procedures to be simple, accessible, and aligned with real-world task steps makes safer performance the natural default.
- Unrealistic timelines. Production targets, service expectations or job scheduling may create time pressure that makes shortcuts feel necessary. Reviewing capacity, sequencing and workload planning ensures that safe systems of work are achievable within the time available.
- Insufficient supervision. Supervisors may have limited visibility of work taking place, or too many direct reports to support effectively. Strengthening supervisory competence and ensuring appropriate ratios supports consistent reinforcement of standards and supports early correction.
- Conflicting operational priorities. Employees might be told safety is the priority but experience stronger pressure to prioritise throughput, speed, or output. Aligning business drivers (including KPIs and performance expectations) with safe behaviours removes this conflict and supports safer decision-making.
By addressing these factors, organisations can make meaningful changes that improve the reliability of work systems. The HSE guidance is clear that improving the work environment and system design is often more effective than relying on individuals to change their behaviour alone.
How HSG48 drives learning culture
Using HSG48 as the framework for investigation supports a culture where the aim is to learn, not to judge. Instead of looking backwards to allocate blame, the focus shifts towards understanding context and strengthening systems to prevent harm in the future.
This approach is supported by wider HSE research on safety culture, which highlights that organisations with strong learning cultures capture more intelligence, respond more effectively to emerging risks, and improve risk control measures over time (HSE RR367: A review of safety culture and safety climate literature).
Embedding human factors into investigation practice can help to:
- Reduce repeat incidents. Systemic improvements tend to eliminate conditions that previously allowed error, such as poor sequencing, lack of clarity or time pressure. When root causes are addressed at a system level, recurrence becomes significantly less likely.
- Strengthen risk controls. Investigations that look at work taking place (not just documented procedure) identify where controls break down in practice. This enables organisations to refine controls based on reality, not assumption, making them more reliable and easier for people to follow.
- Improve reporting culture. When frontline workers see that investigations seek understanding rather than blame, they are more motivated to report near misses, concerns and hazards. This increases the volume of insight captured, enabling proactive intervention before harm occurs.
- Build confidence in the investigation process. Fairness and transparency increase trust. When people believe they will be treated consistently, they contribute more openly during investigation interviews, which improves the quality of evidence available and leads to stronger, more targeted improvements.
In this way, HSG48 is a foundation for continuous organisational improvement, where insights from everyday work are used to enhance resilience and shape safer operations.
Prevent future harm with HSG48-aligned investigation training
Effective accident and incident investigation requires strong skills in evidence gathering, interviewing, case analysis and understanding the human factors that shape real-world work. Applying HSG48 human factors principles improves the accuracy of findings, the quality of learning and the strength of risk controls.
Our Incident and Accident Investigation Training develops these capabilities in a practical and structured way, using real case studies, relevant legal context and proven methodologies to turn investigation outcomes into meaningful preventative action.
This course can be tailored to your organisation and delivered via eLearning, face-to-face at a venue of your choice or through a virtual classroom. Find out more about Incident and Accident Investigation Training on our website or contact us on 0203 011 4242 / info@praxis42.com
Adam Clarke
Managing Director (Consulting)
