What Is Your Fatigue Risk Tolerance? Uncovering a Secret to Cultivating a Safer and Healthier Work Environment


Key Takeaways:

  • Fatigue risk tolerance refers to the acceptable level of risk related to fatigue within an organization’s operations.

  • Understanding and defining your organization’s fatigue risk tolerance level is a critical first step to making informed decisions about the safety and performance of your operation.

  • Being able to understand, quantify and communicate the potential impact of fatigue is important when creating a risk-informed operation that will improve safety and performance.

Fatigue risk tolerance can vary depending on the nature of the work, the relevant regulatory requirements, if any, and the extent of the potential consequences of fatigue-related incidents and errors. One organization's risk tolerance level will be different from the next organization’s level. For example, fatigue-related accidents in the transportation sector can be catastrophic, resulting in a lower fatigue risk tolerance than in a warehouse environment.
There can be multiple risk tolerance levels in a single operation when there are different job tasks with varying levels of risk. One company may have truck drivers, dispatchers, and warehouse workers, all of whom are responsible for different job tasks. Fatigue can impact all of them, but the consequences of making a mistake will be vastly different with each of them.

How to Define Your Fatigue Risk Tolerance

  1. Identify the Safety Risks Associated with Fatigue in Your Workplace

Identifying fatigue hazards, the areas of an organization’s opertions that have fatigue risk, is best accomplished by conducting a systematic Fatigue Risk Assessment. A Fatigue Risk Assessment first identifies and then evaluates the different factors, both physical and mental, that contribute to workplace fatigue risk.

When conducting a Fatigue Risk Assessment, five key areas of fatigue risk need to be controlled to successfully mitigate the inherent costs and liabilities of fatigue in an extended hours operation (See Figure 1).

 Figure 1: The 5 Defenses of a Fatigue Risk Management System


A Fatigue Risk Assessment needs to address all five of these key areas of risk. This can be accomplished using a combination of methods, including:

  • An Assessment of the Current Organizational Policies and Procedures. Determining if current organizational policies and procedures align with industry best practices and regulatory requirements is important to uncovering missed opportunities for reducing risk. This assessment includes staffing and scheduling policies and procedures, fatigue and sleep training curriculum, among other items.

  • Surveys and/or Interviews. Gathering insights into workers’ experiences with fatigue clarifies the front-line everyday experience and helps define priorities when assigning resources.

  • An Analysis of Work Schedules and Rosters. Determining if the staffing levels and schedules worked provide sufficient rest helps to identify schedule-induced fatigue. This is best accomplished using a biomathematical fatigue risk model like the Circadian Alertness Simulator (“CAS”), which assigns an objective fatigue risk score based on scientific principles (for more information please read our FAQs about CAS).

  • An Evaluation of Fatigue Monitoring Tools and Technologies. Tools and technologies currently used in the operation need to be identified and evaluated to determine the extent they help to mitigate fatigue risk;

  • An Analysis of Accident and Other Safety Incident Data. Identifying patterns or trends of accidents and other safety incidents related to fatigue helps to uncover the policies and programs needing to be refined and/or developed to enhance fatigue risk mitigation.

  1. Determine the Likelihood and Severity of Potential Consequences

After identifying the fatigue hazards associated with the five key areas of risk, it is important to determine the likelihood and severity of the potential consequences of an accident or other safety event related to each hazard. This will involve the assessment of the multiple organizational (e.g., staffing levels, scheduling factors, etc.), and personal (e.g., fit-for-duty, education/training, etc.) factors.

Some tasks are inherently more demanding and require higher levels of alertness. For example, fatigue-related accidents can have catastrophic consequences, including loss of life and property damage for safety-critical industries like aviation, trucking, healthcare, and manufacturing. And in other industries, the risk of injury from a fatigue-related event is less (e.g., the need for First Aid).

Similarly, productivity losses from fatigue-related safety events can range from a minor production loss resulting from increased absenteeism to a complete shutdown of production with significant financial cost. In addition, increased healthcare costs, lawsuits, and breach of contract issues all contribute to financial costs and therefore need to be assessed.

  1. Quantifying Fatigue Risk

Quantifying fatigue risk at the time of a safety incident using a biomathematical model provides an objective assessment rather than relying on subjective observations or self-reporting. Concrete data can help to predict when fatigue is more likely to contribute to an accident or safety incident and can help to uncover related trends (e.g., time-of-day, seasonality, department, etc.).

Identifying safety incident trends facilitates early detection and allows for proactive intervention strategies to be implemented, such as scheduling adjustments, increased rest break, or the redistribution of workload.

Data about safety risk trends can inform the design, development, and implementation of effective fatigue-mitigating strategies, optimizing an FRMS. In addition, this data enables an organization to allocate resources more thoughtfully and evaluate the effectiveness of fatigue-mitigating initiatives.

Mini Case Study: Fatigue Risk Tolerance Can Differ by Type of Safety Incident

The level of acceptable fatigue risk in an organization can vary, depending on the job task. One of Circadian’s forward-thinking clients asked us to incorporate CAS, Circadian’s biomathematical fatigue risk model into an analysis of its safety incidents across multiple departments, covering a variety of job tasks.

We found potential variable levels of acceptable risk, depending on the department and the job task:

  • Cognitive errors were up to 25 times more likely to occur when workers had “extremely high” fatigue scores than when workers had “high” or “average” fatigue scores.

  • Workers with “extremely high” fatigue levels were up to 16 times more likely to cause equipment damage when doing physical work than workers with “high” or “average” fatigue scores.

  • Workers with “extremely high” fatigue levels, conducting all different job tasks, were up to 10 times more likely to experience an on-the-job injury than workers with lower fatigue scores.

These findings helped our client to determine its fatigue threshold for their different types of safety incidents and provided invaluable information to consider as their fatigue risk-informed, performance-based safety culture evolves.

Do you know your organization’s fatigue risk tolerance?

Defining an organization’s Fatigue Risk Tolerance is an important step when developing a fatigue risk-informed, performance-based safety culture. Uncovering opportunities to shore up an organization’s key defenses against fatigue risk and objectively quantifying fatigue risk at the time of safety incidents helps to clarify tolerance levels of fatigue risk, informs the design and development of targeted interventions, and cultivates a safer and healthier work environment for a workforce.

Fatigue is one of the most prevalent causes of human error-related accidents, incidents, and injuries – costing billions of dollars annually. Companies often have an incomplete picture of how pervasive fatigue is in their operation because it is often under-reported and under-investigated after safety incidents. Defining an organization’s fatigue risk tolerance will guide the strategic assignment of resources and optimize the effectiveness of fatigue-mitigating programs.

For over 40 years, CIRCADIAN® has been at the forefront of enhancing 24/7 workforce performance and safety solutions, guiding organizations in effectively defining their fatigue risk tolerance. Our deep-rooted expertise in shift schedule optimization and fatigue risk management positions us as your ideal partner in this journey.

Reach out for a complimentary 15-minute consultation and learn more about the steps involved in defining your organization’s threshold for fatigue risk!

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