Requirements define things that a product or service is supposed to do to satisfy the needs of the client and deliver expected business value. A more formal definition is given by the International Institute of Business Analysis (IIBA) in “A Guide to the Business Analysis Body of Knowledge”:
“A requirement is:
(1) A condition or capability needed by a stakeholder to solve a problem or achieve an objective.
(2) A condition or capability that must be met or possessed by a solution or solution component to satisfy a contract, standard, specification, or other formally imposed documents.
A documented representation of a condition or capability as in (1) or (2).”
That is all well and good and I'm not going to challenge the definition. I assume it does what it is supposed to do. But let me offer a different perspective for your consideration and practical application. I believe we execute a complex project to solve a critical problem heretofore unsolved or take advantage of an untapped business opportunity. Two things link the deliverables:
Generating business value is really the only measure of project success. I've long felt that the criterion for defining project success as meeting a specification within the constraints of time and cost is misdirected. It really ignores the business, the client, and organizational satisfaction. ...