The FRAM is based on the four basic principles described below:
The Principle of Equivalence of Successes and Failures
Failure is normally explained as a breakdown or malfunctioning of a system and/or its components. This view assumes that success and failure are of a fundamentally different nature. FRAM – and Resilience Engineering – acknowledges that things go right and wrong in basically the same way. The fact that the outcomes are different does not mean that the underlying processes must be different. The Principle of Approximate Adjustments explains why that is so.
The Principle of Approximate Adjustments
Many socio-technical systems are intractable. The conditions of work therefore never completely match what has been specified or prescribed. Individuals, groups, and organisations normally adjust their performance to meet existing conditions (resources, demands, opportunities, conflicts, interruptions). Because resources (time, manpower, information, etc.) always are finite, such adjustments will invariably be approximate rather than exact. The resulting performance variability is the reason why things go right, but also the reason why things go wrong.
The Principle of Emergence
The variability of normal performance is rarely large enough to be the cause of an accident in itself or even to constitute a malfunction. But the variability from multiple functions may combine in unexpected ways, leading to consequences that are disproportionally large, hence produce a non-linear effect. Both failures and normal performance are emergent rather than resultant phenomena, because neither can be attributed to or explained only by referring to the (mal)functions of specific components or parts.
The Principle of Functional Resonance
The variability of a number of functions may every now and then resonate, i.e., reinforce each other and thereby cause the variability of one function to be unusually high. The consequences may spread through tight couplings rather than via identifiable and enumerable cause-effect links, e.g., as described by the Small World Phenomenon. This can be described as a resonance of the normal variability of functions, hence as functional resonance. The resonance analogy emphasises that this is a dynamic phenomenon, hence not attributable to a simple combination of causal links.
Functional resonance is the detectable signal that emerges from the unintended interaction of the normal variabilities of many signals.