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Systems Thinking for Safety/Functional Resonance Analysis Method (FRAM)

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The Functional Resonance Analysis Method or FRAM (Hollnagel, 2004 & 2012) provides a way to describe outcomes using the idea of resonance arising from the variability of everyday performance. To arrive at a description of functional variability and resonance, and to lead to recommendations for damping unwanted variability, a FRAM analysis consists of five steps (Hollnagel, 2014):

  1. Identify and describe essential system functions, and characterise each function using the six basic characteristics (aspects). In the first version, only use describe the aspects that are necessary or relevant. The description can always be modified later.
  2. Check the completeness / consistency of the model.
  3. Characterise the potential variability of the functions in the FRAM model, a well as the possible actual variability of the functions in one or more instances of the model.
  4. Define the functional resonance based on dependencies / couplings among functions and the potential for functional variability.
  5. Identify ways to monitor the development of resonance either to dampen variability that may lead to unwanted outcomes or to amplify variability that may lead to wanted outcomes.

FRAM is based on four principles:

  1. the equivalence of failures and successes (see also Principle 10. Equivalence)
  2. the central role of approximate adjustments (see also Principle 8. Performance Variability)
  3. the reality of emergence (see also Principle 9. Emergence)
  4. functional resonance as a complement to causality

The FRAM does not imply that events happen in a specific way, or that any predefined components, entities, or relations must be part of the description. Instead it focuses on describing what happens in terms of the functions involved. These are derived from what is necessary to achieve an aim or perform an activity, hence from a description of work-as-done rather than work-as-imagined. But functions are not defined a priori nor necessarily ordered in a predefined way such as hierarchy. Instead they are described individually, and the relations between them are defined by empirically established functional dependencies.

Source: FRAM website

Further reading

Frost, B. and Mo, J. P. T. (2014). System hazard analysis of a complex socio-technical system: The Functional Resonance Analysis Method in hazard identification. Australian System Safety Conference, Melbourne Australia. 28 — 30 May 2014.

Hollnagel, E. (2004). Barriers and accident prevention. Aldershot, UK: Ashgate. (Chapter 6.)

Hollnagel, E. (2012). Functional Resonance Analysis Method: Modelling complex sociotechnical systems. Ashgate.

Hollnagel, E. (2006). Capturing an Uncertain Future: The Functional Resonance Accident Model

The ETTO Principle: Efficiency-Thoroughness Trade-Off Erik Hollnagel, 2013


The Functional Resonance Accident Model