Keywords: ethical analysis, ethical responsibility, fault tree analysis, FTA, probabilistic risk assessment, professional ethics, professionalism, reliability, trustworthiness, safety, engineered systems
The epistemology of fault tree analysis: an ethical critique
Fault tree analysis (FTA) is one of the preeminent methods for testing the reliability, trustworthiness, and safety of engineered systems. Given their pervasiveness as a major tool for assessing the risks of technology, it is imperative that methodologies such as FTA are valid and sound. If a safety assessment based on an FTA is erroneous, the system may fail to work as expected. In this paper I submit FTA to critical scrutiny. Through a detailed step-by-step investigation, it is shown that the FTA methodology rests on numerous unproven, even false assumptions. The paper sketches out a set of ethical principles for risk assessment professionals, which, if followed, will allow them to meet their professional and ethical obligations to consider the impacts of risk on all of the stakeholders involved.