Requirements Engineering is key success factor for developing critical systems. Traditional development processes, that achieve innovation and quality through a cumbersome process, are no longer appropriate. Innovation in increasingly complex systems under cost pressures and global competition requires continuous focus on value and cost. It starts with the requirements that are not "collected", but must be developed together with relevant stakeholders. Requirements engineering must therefore be enriched today with methods from Lean Management.
Lean Requirements Engineering begins with a systematic elaboration of the actual needs and value. For example, misunderstood quality requirements create problems in usability and performance. Without a tight coupling and collaboration of product management and development the resulting products do not match the market needs. Requirement changes are detected too late and lead to unnecessary rework and non-conformance cost. Since many processes due to the high combinatorial complexity and a rather low standardization and its ad-hoc nature are difficult to model, Requirements Engineering must massively support the Sales Function. We present experiences and benefits of Lean Requirements Engineering with projects at Siemens AG. We demonstrate with practical examples and industry experiences, how Lean Requirements engineering is implemented. Thus, the cost of rework can be reduced by approximately 30%. The experiences provided in this presentation can be transferred to other projects and environments.