Bowtie Analysis

A less formal variation of Cause-Consequence Analysis is the “Bow-Tie” technique. It similarly combines two methodologies presented in earlier sections, Fault Tree Analysis and Event Tree Analysis, and uses the format of an incident investigation and root cause analysis technique known as Causal Factors. The Bow-Tie analysis offers a cost-effective approach for a screening hazard evaluation of processes that are well understood. This approach is a qualitative hazard evaluation technique ideally suited for the initial analysis of an existing process, or application during the middle stages of a process design.
Reference: CCPS: guidelines for hazard evaluation procedures, third edition
Technical Tools/Risk Assessment/Quantitative Risk Assessment/Frequency Techniques