Does your software project have a vision statement? It’s that document that defines a system and summarizes predicted benefits, risks, goals, scheduled milestones, stakeholders, etc.
If your team doesn’t have a vision statement for the software under development, they lack a basic roadmap to guide them toward the end result. A good vision statement can help prevent a lot of arguments and help mitigate a lot of risks.
How formal the statement should be depends on the organization, its culture and the scope of the software. If you’re developing an enterprise application for a large organization, take my advice and make the vision statement a formal, in-depth document.
James Shore offers a segment from his book, The Art of Agile Development called Vision. It presents a simple and informal approach to vision statements.
Process Impact offers a complete vision and scope document template (Microsoft Word format). It is much more formal and detailed.
Vision statements are often overlooked and that’s too bad. They should be written before or in conjunction with the high-level requirements. Be as formal or informal as needed. Keep it concise and distribute it to senior management.
Treat it as a living document to be fine tuned as the project evolves.
Oh, one more thing — if the vision changes drastically over time, you’re project is in a lot of trouble.