Frequently made Tripod Beta mistakes in health care and how to deal with them

Guest blog by Tripod Beta assessors Ir. E.H.J. (Ed) Janssen and John Sherban P.Eng.

In reviewing Tripod Beta analyses in the health care industry (e.g. hospitals), we came across some frequently made mistakes. Collecting information on the symptoms and diagnosing the cause are often seen as the most important barriers to prevent the end event – to minimize the harm. Once a correct diagnosis is available, the organization and patient rely on the competency of the practitioner(s) supported by the established protocols. Missing, incorrect, or incomplete information is often seen as a missing or failed barrier. However, from a theoretical point of view based on Tripod Beta concepts, this is not the preferred way to model these incidents.

The complexity of the problem

From a theoretical point of view based on Tripod Beta concepts, such information and the subsequent diagnosis cannot be barriers to prevent or minimize the harm to a patient, because these cannot by themselves stop the harm progression or energy flow. (Refer to the definition of a Tripod Beta barrier and the requirement for direct functionality.) The business processes of information gathering and diagnosis correctly belong on the Tripod Beta precondition level. Possible reasons for this confusion are:

  • The analysts do not make a clear distinction in the objectives for their analysis. For example, is the objective to analyze the harm to the patient or is it to analyze the process disruption during the collection of the information required for diagnosis?
  • Differences in the definitions and terminology used by different analysis methodologies, and/or with general usage of common words.

The solution

Generally speaking, there are multiple options, besides the freedom of phrasing options, to arrive at a correct Tripod Beta tree (i.e. incident model) of an incident in a health care context. For example:

  1. Using a Tripod tree where the main event is described as some ‘Preventable harm to the patient’. In such a tree, the issues associated with gathering the required information, and the subsequent diagnosis based on this information (both of which could be missing, incomplete, or incorrect) can be dealt with at the Tripod precondition level.
  2. Modeling the incident with two separate Tripod Beta trees. The first would be a Tripod tree where the end event describes the error(s) in the processes of gathering the required information or the diagnosis. The second could be a separate Tripod Beta tree such as that outlined as the first option mentioned above with the information from the first tree included in summarized form at the precondition level in the second tree.
  3. Using a combined Tripod tree where the process disturbance is modeled in the first event (Trio), and the harm to the patient is modeled in a following event (Trio).

Examples of Tripod Beta trees in health care

We attempt to demonstrate some correct ways to deal with these issues by presenting a few practical examples. Please find these examples in the white paper that can be downloaded by filling out the form below.

More Tripod Beta examples are welcome. Please send them to or so the examples can be shared on the Tripod Foundation website.

A proactive risk assessment approach

Besides working on incident analyses in the health care sector, Ed Janssen is also closely involved in a project that supports health care organizations to make effective proactive risk assessments by using the bowtie risk assessment method. Learn more about this Patient Safety Bowties project.


2018-04-04T10:12:21+00:00 Blog|

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