Fatigue Risk Management: Using Reason to Determine the Cause of Human Error

Sleep deprivation is an issue that is often ignored, yet frequently the root cause of decreased productivity, accidents, incidents and mistakes which costs the global workforce billions of dollars each year.

Often times, managers and supervisors misattribute fatigue-related operational errors as isolated events caused by a single individual, rather than a systematic failure. Other times, increased accident rates and workforce problems are dismissed as being unrelated to worker fatigue.

Using logic presented by James Reason, a distinguished professor of psychology at The University of Manchester and author of many important books, including Human Error (1990), we can better understand the root cause of fatigue-related errors.

Analyzing Fatigue-Related Errors with Reason

James Reason proposed two possible approaches to the problem of human error: the person approach and the system approach.

The person approach focuses on the premise that an error is caused by a single individual, whether it be due to forgetfulness, inattention, negligence, and other personal lapses.

The system approach focuses on the premise that humans are fallible and errors are to be expected; therefore, errors are consequences of systematic failures and the root cause of errors ultimately falls on the system rather than the individual.

Reason developed the Swiss cheese model of accident causation to illustrate that although multiple layers of defense lie between hazards and accidents, flaws, or ‘holes’, can exist in each layer. When these “holes” align, a pathway emerges for accidents to occur (Figure 1).

Figure 1. James Reason’s Swiss Cheese Model
James Reason Swiss Cheese Model

Given the nature of operational defenses, holes in the defense layers are dynamic and constantly opening, closing, and shifting within an organization – requiring an organization to continually re-evaluate the integrity of their defense systems.

Using Reason’s logic, operational control should be focused on changing the conditions under which individuals work rather than trying to change each individual. Under this model, incident investigation should focus not on who made an error, but rather how and why the systematic defenses failed to prevent the incident.

The How and Why of Human Error

Holes in the defense layers arise from two outcomes: active failures and latent conditions. Active failures are the dangerous acts of individuals – such as: lapses, errors, or procedural deviations. The impact of active failures on the integrity of a defense system are usually temporary.

Latent conditions are the result of decisions made by the management team of an organization. These decisions may lead to unfavorable conditions – such as understaffing and excessive overtime – that can lead to long-lasting weaknesses in the defenses (i.e. fatigued workers, unworkable procedures). Latent conditions can go unnoticed or ignored for many years, even though latent conditions are generally easier to identify and rectify than active failures.

Applying the Swiss Cheese Model to Fatigue Management

When applying Reason’s logic to fatigue management, a fatigue-related accident or incident is the end point of a causal chain of successive lapses in a defense system.

At the end of the day, both an organization and its employees share a responsibility to prevent fatigue to maintain a safe operation.

An organization is responsible for developing a comprehensive defense system against fatigue; while its employees are responsible for arriving to work alert and fit-for-duty.

Developing an Effective Fatigue Risk Management System

A fatigue risk management system (FRMS) is a data-driven, risk-informed, safety performance-based program that reduces the risk of fatigue-related incidents in 24/7 operations. An FRMS continually monitors and reduces fatigue risk from both an organizational and individual approach.

An effective FRMS builds upon organizational policies and procedures to monitor, mitigate, and report worker fatigue and fatigue-related incidences.

When developing or reviewing an FRMS, an opportunity exists to identify the presence (or absence) of necessary defense mechanisms in the FRMS. A fully integrated FRMS provides five equally-critical layers of defense (Figure 2):

  1. Workload-staffing balance
  2. Shift schedule optimization
  3. Employee fatigue training and sleep disorder management
  4. Workplace environmental design
  5. Fatigue monitoring and alertness for duty

Figure 2. CIRCADIAN® 5 Defenses FRMS DesignFRMS

A successful FRMS also has the following seven key characteristics (Lerman et al.):

  1. Science based – Supported by established peer-reviewed science

  2. Data driven – Decisions based on collection and objective analysis of data

  3. Cooperative -- Designed together by all stakeholders

  4. Fully Implemented – System-wide use of tools, systems, policies, procedures

  5. Integrated -- Built into the corporate safety & health management systems

  6. Continuously improved – Progressively reduces risk using feedback, evaluation & modification

  7. Owned – Responsibility accepted by the entire management team of an organization

The seventh key characteristic, management ownership, is particularly critical as the development, implementation, and management of a FRMS requires the involvement of multiple departments of an organization.

Because of this, it’s important that the entire management team of an organization embraces a commitment to fatigue risk management as a critical component to the organization's overall safety and health management system.

Through properly implementing a comprehensive FRMS, an organization stands to significantly reduce the safety risks and profit losses associated with fatigue in a way that provides a win-win scenario for both management and workers.

White Paper: Evolution of Fatigue Risk Management Systems

Download your copy of our white paper “Evolution of Fatigue Risk Management: The “Tipping Point” of Employee Fatigue Mitigation” to learn more about implementing operational defenses against fatigue.

Fatigue Risk Management White Paperdownload fatigue risk management white paper


CIRCADIAN® is the global leader in providing 24/7 workforce performance and safety solutions for businesses that operate around the clock. Through a unique combination of consulting expertise, research and technology, software tools and informative publications, CIRCADIAN helps organizations in the 24-hour economy optimize employee performance and reduce the inherent risks and costs of their extended hours operations.

Fatigue Risk Management System

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