What are requirements?

As project managers and business analysts, we know that above all we are ultimately tasked with defining, managing and delivering upon accurate requirements as requested by the stakeholder group.  This begs the question: what is a requirement?

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
3. A documented representation of a condition or capability as in (1) or (2)

A requirement may be unstated, implied by or derived from other requirements, or directly stated and managed. A requirement may describe the current or the future state of any aspect of the enterprise.

One of the key objectives of requirements gathering is to ensure that requirements are visible to, and understood by, all stakeholders.  It is vital that a “requirement” be understood in the broadest possible sense. Requirements include, but are not limited to...

• Past, present, and future conditions or capabilities in an enterprise and
• Descriptions of organizational structures, roles, processes, policies, rules, and information systems.

Furthermore, requirements can be broken down into distinct categories:

1. Business Requirements are higher-level statements of the goals, objectives, or needs of the enterprise. They describe the reasons why a project has been initiated, the objectives that the project will achieve, and the metrics that will be used to measure its success. Business requirements describe needs of the organization as a whole, and not groups or stakeholders within it.
2. Stakeholder Requirements are statements of the needs of a particular stakeholder or class of stakeholders. They describe the needs that a given stakeholder has and how that stakeholder will interact with a solution. Stakeholder requirements serve as a bridge between business requirements and the various classes of solution requirements.
3. Solution Requirements describe the characteristics of a solution that meet business requirements and stakeholder requirements. They are frequently divided into sub-categories, particularly when the requirements describe a software solution:
• Functional Requirements describe the behavior and information that the solution will manage. They describe capabilities the system will be able to perform in terms of behaviors or operations—specific information technology application actions or responses.
• Non-functional Requirements capture conditions that do not directly relate to the behavior or functionality of the solution, but rather describe environmental conditions under which the solution must remain effective or qualities that the systems must have. They are also known as quality or supplementary requirements. These can include requirements related to capacity, speed, security, availability and the information architecture and presentation of the user interface.
4. Transition Requirements describe capabilities that the solution must have in order to facilitate transition from the current state of the enterprise to a desired future state, but that will not be needed once that transition is complete. They are differentiated from other requirements types because they are always temporary in nature and because they cannot be developed until both an existing and new solution are defined. They typically cover data conversion from existing systems, skill gaps that must be addressed, and other related changes to reach the desired future state.