Much of Cedefop's early work involved studying the comparability of vocational training qualifications in Member States. Around 200 occupations were categorised and their equivalence with other occupations and qualifications determined. The assumption was that vocational training policies in Member States would increasingly be brought into line with each other leading to a mutual recognition of qualifications and certificates and development of a common vocational training policy, as foreseen under Article 128 of the Treaty of Rome.