Humans play a vital role in the design, management, maintenance, and operation of technical systems, within the execution and planning of large and complex operations. Humans tend to make mistakes and are generally more complex than technical systems, which makes it difficult to predict and prevent the types of mistakes they might make.  It is therefore important to include the identification of potential human errors and their probabilities into your risk assessment.

What is human error and human reliability?

Human error refers to any action that falls outside procedure or deviates from expected norms. It can result from issues such as improper sequencing, timing mistakes, lack of knowledge, interface challenges, procedural flaws, and other contributing factors. In contrast, human reliability is the probability that an individual performs a task correctly and avoids any actions that could negatively impact the operation.

What is Human Reliability Analysis?

Human Reliability Analysis (HRA) is a systematic identification and evaluation of the possible errors that may be made by operators, maintenance personnel and other personnel in the operation. The primary objectives of a HRA are to systematically identify, analyse, and integrate critical human interactions into the overall risk assessment, and to quantify the likelihood of both successful and unsuccessful outcomes. Additionally, HRA offers insights for enhancing human performance by improving factors such as man-machine interfaces, procedures, training, and the alignment between task demands and human capabilities.

What are the main steps of an HRA?

The first step is to identify critical operations where human errors could potentially lead to incidents or operational issues. Once identified, these operations should be analysed by breaking them down into specific tasks and subtasks. Potential human errors are then assessed, ideally along with their underlying causes and the factors that influence performance. Finally, the likelihood of human error is estimated for each task and for the overall operation.

What are the benefits?

• It provides quantitative estimates of potential and realistic human errors to use in combination with a risk matrix.
• Supports the identification of weaknesses in personnel interfaces with the operation.
• Identifies causes of human errors to support the development of preventive or mitigation measures in the operation planning.  
• It overall improves the value of your risk assessment by including human error factors. 

One effective way to reduce human error is by training personnel through drills conducted before operations begin. To learn more about drills, check out the following article: What are drills and how can we use them? – RoC Consult ApS  

Sources:
Rausand, M. (2011). Risk Assessment: Theory, Methods, and Applications. John Wiley & Sons, Inc.