substantial factor testglossary / SUBSTANTIAL-FACTOR TEST substantial-factor test. Torts. The principle that causation exists when the defendant’s conduct is an important or significant contributor to the plaintiff’s injuries. Cf. BUT-FOR TEST. [Cases: Negligence 380.] 词条贡献者 法律翻译王漾,在一家顶尖英国律师事务所的上海办公室担任全职法律翻译,专注翻译各类与大中华业务有关的法律文件。