Models of Error Causation in Medicine
The Threat and Error Management (TEM) Model and Reason’s Model of Organizational Accident Causation are two theoretical frameworks that have been developed to describe error causation from a multi-factorial systems perspective, taking into account the wide variety of contributing factors that lead to adverse outcomes and accidents. These models have integrated concepts from human factors and ergonomics – based on the principle that “to err is human”. Initially developed for high-risk industries, these models have been adapted to a healthcare setting and serve as important/seminal models that act as guidelines in the study of error analysis.
Reason’s Model of Organizational Accident Causation
In the late 1990s, James Reason developed the Swiss Cheese Model of Organizational Accident Causation – a conceptual framework that has been applied in high-risk industries, including aviation, engineering and healthcare, to describe the context in which errors occur56. Recent studies have applied the SCM to patient safety, as a tool to identify failures in the healthcare system. The SCM describes the process of accident causation as an interaction between both active errors committed by people at the front-end of service delivery and latent conditions caused by poor decisions made by higher management that occur in a complex system. Based on the model, most accidents are caused by a series of failures that occur at several levels within a system: organizational influences, unsafe supervision, preconditions for unsafe acts, and the unsafe acts themselves. In the SCM, a system (represented as a block of cheese) is expected to have a series of barriers (represented as slices of cheese) that act as its defences against failure. There are holes in the cheese slices that represent individual weaknesses in individual parts of the system. Latent and active errors are what create these holes (penetrate the barriers/defences) in the system. When these holes align across several levels of a system, this creates “a trajectory of accident opportunity” that can result in an AE. Reason’s model classified factors contributing to accidents in 3 domains: 1) organizational/systems, 2) local workplace, 3) unsafe acts.
University of Texas Threat and Error Management Model
The University of Texas Threat and Error Management Model (UT-TEMM) model was developed by human factors researchers at the University of Texas as a conceptual framework to understand the interactions between safety and human performance in aviation. The model is based on aeronautical incidents and accident analysis in high-capacity airlines. It’s based on direct observation studies on the flight deck, and is based on the fundamental premise that threats and errors are inevitable components of complex systems, which is why TEM advocates management as opposed to avoidance. There are 3 components of TEM: threats, errors, and undesired states. Within a healthcare context, threats are events or errors that occur outside the influence of the operating team, increasing the operational complexity of the procedure and promoting opportunity for human error. Threats are elements of the system that provide the circumstances in which human error can occur. Types of threat include patient threats, task threats, environmental threats (equipment and resources), culture, and organizational threats.
