measurable and can therefore be estimated. -          It provides an opportunity for you to review your project within the context of your vision. For every item you should be able to answer the question, 'How does this contribute to my project vision?' If the item doesn't contribute to your vision you've either identified a reason to refine your vision, or identified a feature for which the cost to implement should be evaluated against the actual value it brings to your project. -          It provides an opportunity for a third party to review your project within the context of delivering it as a solution. An experienced supplier will be able to review your requirements and discuss recommendations on technical and implementation approaches, highlight items requiring clarity or additional detail (in the above example, how does the customer pay for the order of widgets?) In essence, to solve a problem you first need to understand it. Following a systematic research approach allows you to establish the facts and expose the underlying goals and tasks which will support the development of a solution that is fundamentally focused on the needs of users.