What-If Analysis

The What-If Analysis technique is a brainstorming approach in which a group of experienced people familiar with the subject process ask questions or voice concerns about possible undesired events.
What-If Analysis is not as inherently structured as some other techniques such as HAZOP Studies and FMEA. Instead, it requires the analyst to adapt the basic concept to the specific application. Very little information has been published on the What-If Analysis method or its application. However, it is frequently used by industry at nearly every stage of the life cycle of a process and has a good reputation among those skilled in its use.
Reference: CCPS: guidelines for hazard evaluation procedures, third edition
Technical Tools/Hazards Identification/Scenario-Based Hazard Evaluation Procedures