Causal Model — Cause, Precondition, Effect

Summary

Yamashita et al. propose a causal model with three elements — cause, precondition, and effect — that can represent indirect causal relationships mediated by enabling conditions. It is simpler than FRAM (6-aspect functional resonance analysis) yet more expressive than a plain cause-effect model, making it tractable for non-expert use.

Overview

Existing causal formalisms present a tradeoff:

  • Simple cause-effect: Easy to use, but cannot represent conditional or mediated causation
  • FRAM (Functional Resonance Analysis Method): Captures 6 aspects of causality (Time, Control, Precondition, Resource, Input, Output) but is too complex for non-experts

The proposed three-element model occupies the middle ground.

Main Content

Definition: Cause

An event or factor that directly triggers an effect. Without the cause, the effect cannot occur. In the FRAM analogy, this corresponds to the Input aspect.

Definition: Precondition

An event or factor that is not the direct cause, but whose presence is necessary for the effect to occur. If the cause occurs without the precondition, the effect does not happen.

In FRAM, preconditions cover the Precondition, Time, Control, and Resource aspects.

Definition: Effect

The outcome or consequence that results when both a cause and its required preconditions are present.

Example: Blackout + Medical Equipment

Cause: Blackout (direct trigger) Precondition: Inadequate emergency power supply (necessary enabling condition) Effect: Medical equipment cannot be used

Without the precondition, the effect does not follow from the cause: if adequate backup power exists, a blackout would not disable the medical equipment.

Countermeasure framing: The precondition “inadequate emergency power supply” is elicited as a countermeasure: “install adequate emergency power supply.”

Relationship to FRAM

FRAM AspectMaps to
InputCause
Precondition, Time, Control, ResourcePrecondition
OutputEffect

The two remaining FRAM aspects (Input and Output) map directly to cause and effect, while the other four map to preconditions. This simplification covers most practically important cases in disaster scenarios.

Countermeasure Elicitation Strategy

Rather than asking participants to identify preconditions directly (which requires domain expertise and reflection), the method asks for countermeasures — actions to prevent or mitigate an effect. Countermeasures are interpretations of preconditions from the perspective of intervention:

“Installing adequate emergency power supply” is the countermeasure corresponding to the precondition “inadequate emergency power supply.”

This design choice makes the model tractable for non-experts: it is easier to think of what one would do to prevent something than to identify what enabling conditions were necessary.

Connections

See Also