Requirements are the reasons for projects. The customer has a need that she wants to satisfy and provides the project team with requirements to satisfy that need. It is the function of the project manager and the team to correctly identify all requirements of the project and to provide a plan that, when implemented, will satisfy each of the requirements.
The most important document that customers use to transmit requirements is the statement of work. The SOW is always provided in a formal solicitation, but not usually for an internal project. However, organizations need to make the SOW a part of their operating policies. Lacking that, the project manager, when he is assigned a project, should prepare an SOW outlining the project scope, as he understands it. Then he should get the customer's endorsement before the project is initiated.
Identifying requirements is not difficult when well-written project documentation is available. It does, however, require attention to detail and a thorough review of all the documentation. An important and very useful tool in identifying all the project requirements is the cross-referencing matrix. This matrix helps identify the requirements and provides a way of referencing each requirement to each relevant project document. This way, if the requirement is referred to in more than one document, the descriptions will be consistent. Finally, and perhaps most important, each requirement can be referenced to the WBS to ensure that the requirement is specifically addressed in the project plan.
Poorly written or misinterpreted requirements are the biggest cause of project failure. Properly identifying the customer's requirements, whether the customer is external or internal to the organization, and developing and executing a strong project plan to address these requirements are the major functions of the project manager and her team.