Compare methods

	FMEA	Hazard and Operability Study (HAZOP)	Semi-Quantitative Risk Matrix Analysis
Field	Decision-making	Disaster Studies	Disaster Studies
Family	MCDM	Process / pipeline	Process / pipeline
Year of origin	1995	2016	2019
Originator	Stamatis, D. H.	ICI (1960s practice); codified in IEC 61882 and CCPS guidelines	ISO/IEC 31010 (standardized practice); critical analysis by L. A. Cox
Type	Risk priority via product of O·S·D ratings	Structured guide-word deviation analysis of process designs	Semi-quantitative consequence-likelihood rating and ranking pipeline
Seminal source	Stamatis, D. H. (1995). Failure Mode and Effect Analysis: FMEA from Theory to Execution. ASQ Quality Press ISBN: 978-0-87389-300-8	International Electrotechnical Commission. (2016). IEC 61882:2016 Hazard and operability studies (HAZOP studies) — Application guide (2nd ed.). IEC, Geneva.	International Organization for Standardization. (2019). IEC 31010:2019 Risk management — Risk assessment techniques. ISO/IEC, Geneva.
Aliases	—	HAZOP Study, Hazard and Operability Analysis, Guide-Word HAZOP, Deviation Analysis	Risk Matrix Analysis, Consequence-Likelihood Matrix, Probability-Impact Matrix, Risk Rating Matrix
Related	8	3	3
Summary	FMEA (Failure Mode and Effects Analysis) is a ranking multi-criteria decision-making (MCDM) method introduced by Stamatis, D. H. in 1995. It turns a decision matrix of alternatives scored on multiple criteria into a structured, reproducible result.	A Hazard and Operability Study, or HAZOP, is a structured, team-based examination of a process design that systematically searches for deviations from the design intent and judges whether each deviation could create a hazard or impair operability. Its signature device is the guide word: terms such as 'No', 'More', 'Less', 'Reverse' and 'Other than' are combined with process parameters like flow, pressure and temperature at each part of the system to provoke a complete and disciplined set of 'what if it went wrong this way?' questions. IEC 61882 is the international application guide that defines the technique, its guide words and its workflow, while the CCPS Guidelines for Hazard Evaluation Procedures situates HAZOP among the core hazard-evaluation methods of process safety. The method's power lies in its rigorous, qualitative completeness: by walking every node and every guide word, a multidisciplinary team aims to leave no credible deviation unconsidered.	Semi-quantitative risk matrix analysis rates each risk on ordinal likelihood and consequence scales and combines the two in a grid to assign a risk level that drives prioritization. It is the workhorse of practical risk management: ISO/IEC 31010 lists the consequence-likelihood matrix among its standard techniques precisely because it lets analysts compare many disparate risks quickly without the data demands of a full quantitative model. The 'semi-quantitative' label captures its hybrid character — ordinal categories such as 'rare' or 'catastrophic' are anchored to rough numeric bands, giving more discipline than a purely verbal judgment but far less than a probabilistic calculation. The method's popularity is matched by sharp critique: L. A. Cox's 2008 analysis in Risk Analysis showed that poorly designed matrices can rank risks incorrectly, compress very different risks into the same cell, and even perform worse than random, making careful scale design and consistency checks essential rather than optional.