Human factors in investigations

Why address human factors in investigations?

Incidents and near-misses are opportunities to learn and get better.

My experience as a safety inspector, a role that often involved reviewing company incident reports, was that many investigations simply concluded that the cause (or one of the causes) was ‘human error’. This phrase has been over-used. The late Professor Trevor Kletz famously said that attributing incidents to human error was about as useful as saying that falls are due to gravity. Human error should not be a conclusion of an investigation – it should be the starting point!

By considering human factors in investigations you will gain an understanding of why people behave (and think) the way they do, so that you can prevent future events. Whilst the immediate cause just before the accident occurs may often be a human failure, there will be underlying causes that influence that failure. These causes or contributing factors may be remote in time and space from the accident. Addressing these actions, decisions or events will have the most impact on preventing future accidents.

Investigation is a reactive approach, in the sense that an adverse event has already happened, and the objective is to learn from this event.

Investigations are a useful process to understand what really happens and how work is really done.

The stages of an incident investigation

The process for investigating and analysing incidents will vary across organisations, but it will typically involve two main stages: (1) gathering and organising information on what happened, when, to whom etc. and (2) analysis of that information to understand why the event occurred and make recommendations. This may be an iterative process – if you find that during the analysis phase your understanding is incomplete, don’t be afraid to seek further information.

The role of the investigation team is to make recommendations for change – wider stakeholder engagement is necessary to turn these into effective actions.

Information should be obtained from a range of sources, including interviews, observation, and documents. This is used to build a description of what happened (not just what didn’t happen!).

How to address human factors in investigations

If we are to learn as much as possible from investigations, then human factors must be addressed with some structure and rigour. There are tools and approaches that will assist, but ultimately, the investigation team must have some competence in human factors. Ideally, investigation teams should include human factors expertise from the outset, rather than part-way through the investigation once engineering or technical causes have been addressed.

In order to improve the quality of how human factors is addressed in investigations, I’d recommend that training for investigators should include the following:

  • The types of human failures
  • An understanding of the capabilities and limitations of human beings
  • The factors that influence human failures (Performance Influencing Factors)
  • A basic understanding of the key human factors topics
  • An understanding of the ‘human error’ concept and its limitations
  • Just Culture or Fair Culture frameworks (see the ‘Just Culture’ section on this page)
  • Mind traps or cognitive biases and decision-making.

Reviewing the findings from major investigations, such as those described on the Incidents pages, will provide a good grounding into the issues to be considered. However, a good human factors investigation largely depends upon the mindset of the investigators. Understanding that people are part of a wider system is key. If human failures are identified in the investigation, it should be acknowledged that all human failures occur because the systems for preventing them failed in some way. The aim of an investigation is to identify what these systems are, how they are intended to work and how they may have failed.

Many accidents are blamed on the actions or omissions of an individual who was directly involved in operational or maintenance work. This typical but short-sighted response ignores the fundamental failures which led to the accident. These are usually rooted deeper in the organisation’s design, management and decision-making functions”

Reducing error and influencing behaviour, HSG48, HSE, 1999, p.6

The main purpose for investigating an event should be to understand why it happened, not to search for the person(s) responsible. It is not the attribution of blame, but rather the analysis of behaviours, decisions and the underlying factors that help us to understand why an event occurred.

Most people don’t set out to make an error or cause an accident – they just want to get the work done. Generally, people do what they consider to be reasonable at the time – given their knowledge, objectives, mental model, available time and resources etc. They do what makes sense at the time.

Addressing human factors in investigations requires an understanding of the context in which people work.

Investigations should look more widely than the immediate ‘actors’ in the event, and should consider whether behaviours or decisions at the ‘sharp end’ were influenced by management, leadership or organisational deficiencies.

If people cannot see what they need to see, cannot reach what they need to, or do not have all of the required information ‘to hand’, then this may lead to human failures. In the same way, violations are often assumed to be wilful and malicious – whereas in reality they are often a function of poor written procedures, inadequate training, poor supervision and so on.

The aim of addressing human factors in investigations is to identify these wider factors that can predispose human performance issues. For example, if a procedure was not followed, the investigation should explore why. Identifying the deficiency in the system that led this situation and assessing if the same deficiency could affect other procedures will lead to wider learnings.

In order to understand actions and decisions, investigations should identify what factors shaped or influenced the human performance issues (i.e. the relevant Performance Influencing Factors). Key to effective investigations is understanding what made sense to the people involved at the time – and why.

It therefore follows that recommendations should be associated with the underlying or indirect causes, rather than focussing on managing the behaviours or decisions of individual people. Issues such as a lack of competence or inadequate procedures are not root causes – the investigation should continue to seek further information. For example, if it is determined that a key factor was ‘lack of competence’, the investigation should aim to understand why this was the case – what organisational processes failed in order to create that situation? There may have been failures in the selection processes, the training needs assessment or in the training delivery.

The more thorough the level of analysis, the better will be the recommendations.

Finally, in a paper on How not to investigate an accident, Prof. Trevor Kletz (2011) warned: “Don’t think of a possible, or even probable, cause and then look for evidence that supports it”.

Related posts and pages

Further reading

Demystifying Human Factors: Building confidence in human factors investigation. This guidance aims to support the incorporation of human factors into investigations – and compliment the investigation methods that organisations already have in place. It looks at different stages of the investigation process and how maximum learning can be achieved in each stage. Report No. 621, International Association of Oil and Gas Producers (IOGP, 2018).

Learning from incidents, accidents and events, Energy Institute (2016). Learning From Incidents (LFI) is a process whereby employees and organisations seek to understand any negative events that have taken place and then take actions in order to prevent similar future events. This publication (free download when you register) covers the whole LFI process, from reporting and finding out about incidents, through to implementation of effective learning and resulting in changing practices. It guides the reader to understand the human and organisational factors (HOF) causes of an incident through appropriate investigation approaches. This document replaces Guidance on investigating and analysing human and organisational factors aspects of incidents and accidents (Energy Institute, 2008).

Human factors in accident investigations, This information paper seeks to facilitate improvement in the quality of exploration of human factors contributions during investigations, and so contribute to the development of more effective corrective actions. It provides a suggested approach to exploring human factors contributions within accident and dangerous occurrence investigations. Written for the Australian offshore petroleum industry, but applies more widely. National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA, 2016).

Human factors in accident investigations. Extract from UK HSE Inspectors Human Factors Toolkit. Outlines an accident model and provides a series of test-yourself audit questions.

Investigative interview guidance, This interview style is also known as the cognitive interview, based on psychological theory and research for examining the retrieval of information from memory. Although written for patient safety incidents, this short guide is a useful reference for anyone wanting to improve their interview technique. National Patient Safety Agency, 2008.

Learning, candour and accountability. A year after a review commissioned by NHS England uncovered failings at Southern Health Foundation Trust, the CQC reviewed how UK healthcare Trusts investigate and learn from the deaths of people who have been in their care. It examines whether opportunities for prevention of death have been missed, and identify any improvements that are needed. The CQC  weren’t able to identify any trust that demonstrated good practice across all aspects of identifying, reviewing and investigating deaths, and ensuring that learning is implemented. Several of the recommendations apply to all industries. The CQC press release can be found here. Care Quality Commission (2016). 


Up ↑