We now have a professedly unified approach to assigning tort responsibility that treats simple and more complex cases in fundamentally different ways without acknowledging it. The strictly causal component of so-called ‘apportionment of fault’ (the US term) provides no basis for disproportionate assignments of liability but is treated as if it does. Other considerations must actually account for unequal liability assignments in multi-actor cases. But these other elements are often role-based, reflecting whether and how defendants joined in a complex but single pattern of events that were collectively the sufficient cause of an injury.
Utz, Stephen G, Causation and Fault Apportionment (February 4, 2017).