# Arguing from Hazard Analysis in Safety Cases: A Modular Argument Pattern

## TL;DR

This paper introduces a modular argument pattern that integrates hazard analysis techniques like FTA, FMEA, and STPA to improve the clarity and confidence of safety cases by making reasoning more traceable and concrete.

## Contribution

It presents a novel argument pattern combining multiple hazard analysis methods and their results to enhance safety argument confidence and traceability.

## Key findings

- Pattern effectively integrates hazard analysis techniques.
- Improves traceability and confidence in safety arguments.
- Facilitates formal analysis and computer-assisted safety case construction.

## Abstract

We observed that safety arguments are prone to stay too abstract, e.g. solutions refer to large packages, argument strategies to complex reasoning steps, contexts and assumptions lack traceability. These issues can reduce the confidence we require of such arguments. In this paper, we investigate the construction of confident arguments from (i) hazard analysis (HA) results and (ii) the design of safety measures, i.e., both used for confidence evaluation. We present an argument pattern integrating three HA techniques, i.e., FTA, FMEA, and STPA, as well as the reactions on the results of these analyses, i.e., safety requirements and design increments. We provide an example of how our pattern can help in argument construction and discuss steps towards using our pattern in formal analysis and computer-assisted construction of safety cases.