The paper examines the impact of the transformations in doctoral education in the arts, humanities and social sciences in the United Kingdom over the past decade. It focuses on the introduction of formal research training and codes of research practice and in the first longitudinal candidate cohort study examines their impact on doctoral outcomes, especially Ph.D. submission rates. Results from this quantitative study show that engagement with research training, completion of a project outline and plan and appointment of a supervisory team were statistically positively associated with submission of the thesis within four years. It is concluded that the professionalisation of doctoral education by research training and codes of research practice has had a positive impact on doctoral educational outcomes. (Contains 1 figure and 5 tables.)