The Tripod Beta method was developed on the bases of research done in the late 80’s and early 90’s into human behavioral factors in incidents. The research was commissioned by Shell International and executed by the University of Leiden and Victoria University in Manchester. The research question was: ‘Why do people make mistakes?’ The answer to that question was because organizations expose them to an imperfect working environment. This does not mean people will not make mistakes when they work in a ‘perfect’ working environment, but it is the aspect were organizations have control over and therefor can make changes for improvement.
The Tripod Beta method analyzes which barriers have broken during an incident, the error or mistake made, the working environmental aspect that encouraged this and finally the latent failure in the organization that caused that mechanism. A Tripod Beta analysis process follows three steps:
1. Identify the chain of events preceding the consequences
2. Identify the barriers that should have stopped this chain of events
3. Identify the reason of failure for each broken barrier. This should be broken down in the human failure (Active Failure), the working environmental aspects (Preconditions) and the Latent Failure in the organization.
For the identification of the reason why the barriers broke the Human Error theory is kept in mind. It is investigated what error was made, what failure in the working environment caused this and what latent failure caused this to be present. The core of a Tripod analysis is a ‘tree’ diagram representation of the incident mechanism which describes the events and their relationships.