If your work in managing a project identifies issues, defects or required changes in the model rather than internal to a single element, you can represent these using Change, Issue or Defect elements as structured comments with which you can track and manage the problems.
- A Change element corresponds to a change in requirements for the current system
- An Issue element corresponds to a failure to match the requirements for the current system due to newly arisen organizational or legal factors such as staffing problems, changes in laws or guidelines, or business unit restructuring
- A Defect element corresponds to a failure to match the requirements for the current system due to a flaw in the model, system or process, such as a missing element or module, or no inclusion of a necessary actor
You can also define any specific work to be done in researching or resolving the problem using Task elements, and assign resources to these or directly to the Change, Issue or Defect elements internally, in Resource Allocation, or externally as Actors.
The use of maintenance elements provides a broad scope for managing changes, defects and issues, providing the facility to fully define the problem and its resolution with Linked Documents, both internal and external Notes, and Composite Structure diagrams including Interaction and Activity diagrams.
You can create Change, Defect and Issue elements in various UML diagrams (especially Maintenance diagrams) and connect them using Realization, Dependency, Aggregation and other relationships to show what model elements each problem affects and how each is resolved. Within the element 'Properties' dialog for Changes, Defects and Issues you can identify the problem as the element name and record relevant management details, such as owner and dates.
A useful tool in managing problems and changes is the Relationship Matrix, in which you might - for example - link staff (Actors) through Realization connectors to Issues. Each highlighted square in the Matrix indicates the responsibility of a staff member to work on or correct a named Issue.