The underlying reason for the user error is the most important factor to determine during the post-incident review, as this helps the information security manager to understand the root cause of the breach, and to implement corrective and preventive actions to avoid similar incidents in the future. The underlying reason for the user error may be related to the lack of training, awareness, guidance, or motivation of the user, or to the complexity, usability, or design of the system or process that the user was using. By identifying the underlying reason for the user error, the information security manager can address the human factor of the information security program, and improve the security culture and behavior of the organization. The time and location that the breach occurred, evidence of previous incidents caused by the user, and appropriate disciplinary procedures for user error are not the most important factors to determine during the post-incident review, as they do not provide a comprehensive and holistic understanding of the breach, and may not help to prevent or reduce the likelihood or impact of future incidents. References = CISM Review Manual 2023, page
1671; CISM Review Questions, Answers & Explanations Manual 2023, page 382; ISACA CISM - iSecPrep, page 233