The document discusses the importance of quality assurance during the requirements engineering phase of the software development lifecycle. It states that having no quality checks of requirements can lead to issues down the line if the design and implementation are based on incorrect requirements. Issues are more costly to fix the later they are found. Quality assurance approaches during requirements include constructive techniques like templates and prototyping to minimize mistakes during creation, and analytical techniques like inspections and formal verifications to detect issues in completed requirements. Early quality assurance improves requirements quality and overall system quality.