The decision to write an audit plan should primarily be based on what factor?

While it is important for internal auditors to have experience in auditing, the most significant factor in deciding to write an audit plan is the results of previous audits. This factor provides insight into the organization's past performance, areas that may require more focus, and any systemic issues that need to be addressed. By analyzing the outcomes of previous audits, auditors can prioritize areas that may have shown weaknesses or non-conformities, thereby enhancing the effectiveness and efficiency of the audit process.

Incorporating lessons learned and trends from past audits helps ensure that the audit plan is relevant and targeted, ultimately leading to continuous improvement in quality management systems. It allows the organization to allocate resources effectively and ensures that critical areas are addressed, aligning with the goals of ISO 9001 in promoting continual improvement and customer satisfaction.

Although the experience of the auditor is valuable and can influence how the audit is conducted, it does not replace the critical need to base the audit plan on factual data and findings from previous audits, which directly relate to identifying risks and improvement opportunities.