The defining characteristic of the systems integration (SI) approach is to begin with the end in mind. This core feature means understanding what the operational outcome of a project should be and what benefits the users and stakeholders of the system desire. It is often easy to articulate the top-level goals of a project, whether it is a railway, a building or a product. However, in most cases it is impossible to deliver a solution based only on stakeholder expectations and user needs. So, the expectations and needs must be broken down into pieces that form deliverable packages of work. Applying a systems methodology to the breakdown, structure and management of these expectations and needs—in the form of requirements—can provide the difference between delivering on time and on budget, or not delivering at all.
Starting Right With System-Level Requirements
Within the systems engineering and systems integration discipline, requirements engineering (also known as requirements management) aims to avoid pitfalls by developing upfront a set of clear, complete and correct system-level requirements and providing them to those contracted to deliver the work packages (or subsystems). The intention is to ensure that when delivered those packages come together to deliver the desired operational outcomes.
Developing the requirements is done by understanding the capabilities (functions and performance) that represent stakeholder expectations and user needs and determining how the whole system will meet those expectations and needs. Then, an assessment is made to specify the work packages (or subsystems), what those work packages are required to achieve and how those packages must integrate to deliver the capabilities using SI. This holistic process culminates in defining the requirements at the contract level.