What model is primarily used to define the boundaries of a business domain or solution?

The scope model is primarily used to define the boundaries of a business domain or solution because it clearly delineates what is included and excluded in a project or business analysis effort. By establishing these boundaries, stakeholders can better understand the focus and limitations of the project, ensuring that the analysis stays aligned with the intended objectives.

Scope models also facilitate communication among team members and stakeholders by providing a visual representation of the context and extent of the work, which helps prevent scope creep and keeps the project on track. It directly addresses the requirements and expectations related to the business domain, making it a key tool in business analysis planning.

While other models, such as the business model, process model, and functional model, provide important insights into various aspects of an organization or solution, they do not specifically focus on the definition of boundaries. The business model describes how an organization creates, delivers, and captures value, the process model illustrates sequences of business activities, and the functional model addresses specific functions of a system or organization but does not define overall project scope. Thus, the scope model is uniquely suited to define these boundaries.