There are a variety of tools to develop safety and assurance cases. The tools below demonstrate strong core functions for communicating safety cases and formulating statistical analysis and evidence.
ASCE by Adelard
The market leading tool ASCE (Assurance and Safety Case Environment), is designed to simplify the creation and management of cases, and reduce project and system risk through effective communication of the safety argument and associated evidence.
It was developed by Adelard LLP, and is available free of charge for evaluation and academic purposes. Please request ASCE here.
AdvoCATE by NASA
NASA Ames Research Center developed a tool called AdvoCATE for assurance case automation. AdvoCATE is being engineered atop formal foundations for assurance case argument structures, to provide unique capabilities for: a) automated creation and assembly of assurance arguments, b) integration of formal methods into wider assurance arguments, c) automated pattern instantiation, d) hierarchical abstraction, e) queries and views, and f) verification of arguments.
[Ewen Denney and Ganesh Pai, "Tool Support for Automation in Assurance Case Development", To appear in Journal of Automated Software Engineering. (PDF)]
D-Case Editor by DEOS
D-Case Editor is a typed assurance case editor, which has been implemented as an Eclips plug-in using Eclipse GMF. The key features include supporting GSN (Goal Structuring Notation), GSN Pattern Library function and prototype Type Checking function, consistency checking of D-Case description, and monitoring of target systems [DEOS].