Using NESS to overcome the confusion created by the ‘material contribution to harm’ test for causation in negligence

This paper seeks to address the confusion in the debate surrounding the scope of the Wardlaw test of ‘material contribution to harm’. It is argued that this confusion arises because, by asking whether or not the material contribution to harm test is an exception to the but-for test, the debate is asking the wrong question. The but-for test is conceptually inadequate as a test of causation so it prevents us from identifying the causal issues clearly. Instead, Richard Wright’s ‘NESS’ (Necessary Element of a Sufficient Set) test is more comprehensive than the but-for test so it enables us to articulate causal problems clearly and to refocus the debate on the right issues. This paper applies the NESS test, in tandem with a clear definition of damage, to clarify the solution to a range of causal problems.