The Vision document provides a high-level-sometimes contractual-basis for the more detailed technical requirements. There can also be a formal requirements specification. The Vision captures very high-level requirements and design constraints to give the reader an understanding of the system to be developed. It provides input to the project-approval process and is, therefore, intimately related to the Business Case. It communicates the fundamental "whys and what's" related to the project and is a gauge against which all future decisions should be validated.
The Vision document will be read by managers, stakeholders in use-case modeling, and developers in general.
The Vision document is created early in the inception phase, and it is used as a basis for the first draft of the Risk List (see Artifact: Risk List).
The Vision document serves as input to use-case modeling, and is updated and maintained as a separate artifact throughout the project.
An analyst is responsible for the integrity of the Vision document, ensuring that:
A project vision is meant to be changeable as the understanding of requirements, architecture, plans, and technology evolves. However, it should be changing slowly and normally throughout the earlier portion of the lifecycle.
It is important to express the vision in terms of its use cases and primary scenarios as these are developed, so that you can see how the vision is realized by the use cases. The use cases also provide an effective basis for evolving a test case suite.
The original author can be anybody, but when the project is established, the Vision is the responsibility of the system analyst.
Another name used for this document is the Product Requirement Document.
Tailor as necessary for your project's needs. It is generally good practice to keep the Vision brief in order to be able to release it to stakeholders as soon as possible, and to make it easy for stakeholders to review and absorb. This is done by including only the most important stakeholder requests and features, and avoiding detailed requirements. Details may be captured in the other requirements artifacts, or in appendices.
Decide whether feature attributes are documented here or in the Requirements
Management Plan. Decide what information (attributes) to include in the Vision,
and which to manage using requirements management tools.