Definition
Requirements are documented statements that describe the capabilities, conditions, or constraints a system, product, or service must meet to satisfy a contract, standard, or other authority. They define what needs to be built or achieved, providing a clear target for development and testing efforts. In practice, requirements are gathered, analyzed, documented, and managed throughout the project lifecycle to ensure alignment between stakeholder needs and the final solution. Understanding and properly defining requirements is crucial for delivering successful projects, as it prevents scope creep, reduces rework, and ensures the end product meets user expectations. For instance, a requirement for a web application might be that it must load a specific page within three seconds under peak load conditions. This differs from a user story, which focuses on the user's perspective and desired outcome rather than specific technical or functional criteria. Requirements are a fundamental concept tested in project management certifications like PMP and CAPM, as well as in ITIL Foundation.