Causation and Epidemiology
Causation Framework
The substantial factor test applies where multiple causes contributed and but-for analysis would exonerate each. It asks whether the defendant's conduct materially contributed to the result rather than whether the harm would have occurred without it.
The Restatement Third narrowed its application.
Alternative Names:
Substantial Factor Standard, Material Contribution Test
Why it Matters?
The test's expansion beyond its original purpose has drawn criticism, since applying it wherever causation is difficult rather than only where but-for genuinely fails dilutes the causation requirement. The Restatement Third confines it to multiple sufficient cause scenarios and reverts to but-for elsewhere. Which formulation the forum applies determines whether a defendant with a small contribution can be liable for the whole.
Frequently Confused with
Related terms
Frequently asked questions
When should the substantial factor test apply?
What is the criticism of broader use?
