As safety cases evolve to cover the whole of the life cycle, changes will be a frequent occurrence. This presents a significant challenge to System Engineers and the DSM meta-model has been designed to address these challenges. Within the DSM metamodel, these entity types have been defined:
General: Package, query, report, matrix
GSN: Goal, Strategy, Assumption, Justification, Solution, Evidence, Context Arrow, Support Arrow, GSN Diagram
Causality: Causal Diagram, State, Simple Event, Mishap Event, Event Logic, Guard Arrow, Component, Component instance, Trigger Arrow, Sequence Arrow, Causal diagram
Bowtie: Bowtie Event, Threat Line, Control, Control Event, Event, Hazard, Hazard Arrow
Both boxes and arrows are entities, and all entities can be extended with data fields and new relationships. For instance, GSN goals could be associated with their main diagram.