Hazard and Risk Analysis: Which Method Answers Which Question

Six methods, one risk file. PHA, FTA, ETA, FMEA, HAZOP and HACCP each answer a different question, and none of them delivers a finished risk analysis on its own. Under ISO 14971 the quality of an analysis is not decided by methodological breadth but by two things: whether the method fits the question in front of you, and whether its output connects to the risk management file in a way that holds up in an audit.

The full whitepaper works through the six methods, the criteria for choosing between them and the five requirements for a robust interface to the risk analysis. The sections below give an overview of the core topics.

Where hazard analysis sits within the ISO 14971 framework

Where hazard analysis sits inside risk management, and how the supporting methods connect to the final risk report.

Six methods at a glance

PHA, FTA, ETA, FMEA, HAZOP and HACCP, each with its strengths, its weaknesses and the situations it actually fits.

Deep dive: the architecture of an FMEA

From structure and function analysis, through the directed chain of failure mode, cause and effect, to the rating-based release decision.

Method selection and proportionality

Guiding questions for choosing by risk question, product complexity and maturity, instead of regulatory overcompliance.

Method combinations that earn their extra effort

PHA plus FMEA as the foundation, FMEA plus FTA for critical safety questions, FTA plus ETA as a cause-and-effect pairing.

The interface to the ISO 14971 risk analysis

Why a failure mode is not a hazard, and the five requirements for a link that holds: assignability, traceable translation, stability under change, traceability to evidence, and auditability.