Weir (2004) (as part of an historical introduction) notes that the Cambridge exams marked "a British/European preoccupation with the trait, the what we are testing, as against an American preference for the method, the how of testing. This contrast was to last throughout the 20th Century until the Test of English as a Foreign Language (TOEFL) Next Generation programme."
Weir, C.J. 2004: Language testing and validation: an evidence-based approach. Basingstoke: Palgrave Macmillan.