1. professional background: external auditors need to have professional background and knowledge reserves in related disciplines, and be able to accurately evaluate the academic level and research content of dissertations.

2. Academic achievements: External auditors need to have certain academic achievements and research experience, and be able to evaluate the academic value and innovation of dissertations.

3. Academic reputation: External auditors need to have a good academic reputation and academic ethics, and can objectively and fairly evaluate the quality and level of dissertations.

4. Review experience: External audit experts need to have certain review experience and ability, and can independently complete the review of dissertations.