When developing an incident escalation process, the BEST approach is to classify incidents based on:

The best approach to developing an incident escalation process is to classify incidents based on the information assets affected, because this will help to determine the impact and severity of the incidents, as well as the appropriate response and recovery actions. The information assets affected by an incident can indicate the potential loss of confidentiality, integrity, or availability of the information, as well as the legal, regulatory, contractual, or reputational implications. By classifying incidents based on the information assets affected, the organization can prioritize the incidents and escalate them to the relevant stakeholders and authorities.

References = CISM Review Manual, 16th Edition, page 2901; A Practical Approach to Incident Management Escalation2