Until now, modular assurance cases in PREMIS could only be developed from the bottom up. That is, you had to develop the argumentation of all the modules, create interfaces, assign argument elements to the interfaces, and finally bind the modules. The result can be presented in an architecture diagram. This was a long and tedious process.
Starting from version 1.2 of PREMIS, you can also develop modular assurance cases top-down. You can first create argument modules and bind them to interfaces without adding elements within these modules. Module arguments can be created once interfaces and bindings are defined.
The advantage of this approach is the separation of decision levels. Decisions can be made separately about the architecture of the assurance case, and separately about the structure of the arguments in each module. In particular, the former decisions can now be made without going into technical details and without specifying specific claims. In the process of architecture development, empty interfaces are created to connect modules. They are to be filled in the second step, during argument development.
The short video below shows how to create modular assurance cases using the top-down approach in PREMIS 1.2:
PREMIS version 1.2 allows you to easily create assurance case modules while you are in the architecture diagram. In the next PREMIS versions this feature will be extended with adding existing modules, connecting and disconnecting them. The goal is to enable easy assurance case architecture management on the level of argument modules.