This activity addresses:

• Aligning the project team in their understanding of the system.
• Performing a high-level analysis on the results of collected Stakeholder Requests.
• Refining the Vision to capture the key features that characterize the system (see Develop Vision).
• Refining the Use-Case Model to include outlined use cases (see Find Actors and Use Cases).
• Outlining the non-use-case-specific requirements in the Supplementary Specifications (see Develop Supplementary Specifications).
• Beginning to capture the results of the requirements elicitation activities in a more structured manner.

The activities that focus on problem analysis and understanding stakeholder needs create early iterations of key system definitions including the features defined in the vision and a first outline of the detailed requirements. This activity, defining the system, focuses on identifying actors and use cases more completely by outlining their content (see Find Actors and Use Cases), as well as outlining the non-use-case-specific requirements in the Supplementary Specifications (see Develop Supplementary Specifications).

The Glossary is also refined as additional common terms are identified (see Capture a Common Vocabulary).

As you define new requirements, it is important to document any dependencies (e.g.,  Traceability) between these requirements (see  Manage Dependencies).

While it encourages team ownership and commitment to have all members of the project team participate in defining the system, this work is primarily coordinated and conducted by staff playing the System Analyst role. Because this work often requires making tradeoff's between multiple requirements to make best use of the finite development resources, diplomacy, negotiation and mediation are important skills for the system analyst conducting this work.

It should be noted that activities being performed in this capability pattern are not performed in sequence.  In fact, it is more-often the case that these activities are performed concurrently. For example, while identifying actors and use cases (Find Actors and Use Cases), we may encounter requirements that do not naturally align with a particular use case, in which case the requirement may be defined in the Supplementary Specifications (Develop Supplementary Specifications). Conversely, while identifying non-use-case-specific requirements (e.g., system-wide requirements), we may encounter requirements that only apply to a particular use case, in which case the requirement is associated with the use case.