Which type of audit is most extensive and comprehensive?

A system audit is recognized as the most extensive and comprehensive type of audit because it involves a thorough examination of an organization's entire quality management system. This type of audit assesses the effectiveness of the processes and their interactions, ensuring that they conform to established standards and are aligned with the organization's objectives.

During a system audit, the auditor evaluates the overall structure, documentation, processes, and practices. This includes not only reviewing records and policies but also observing operations and engaging with staff to understand how effectively the system is implemented in practice. The comprehensive nature of a system audit means it covers all aspects of quality management, providing insights into compliance, efficiency, and opportunities for improvement.

In contrast, an assessment audit focuses more narrowly on specific areas or processes within the organization, and a vendor survey typically evaluates suppliers rather than the overall system. A full audit may seem comprehensive but does not always imply the same level of detail and breadth as a system audit, which seeks to understand the interplay between all components of the quality management system. Thus, the in-depth approach of a system audit defines its position as the most extensive and comprehensive type.