The 9th CDE workshop at TUDelft focused on doctoral supervision practices and responsibilities. Supervision is universally recognized as critically important, as good supervision is vital for research success, especially PhD research. The meeting had the highest attendance in CDE workshop history. Effective supervision requires teams of supervisors and innovation in doctoral training programs. While the supervisor remains key, assessment and advice should be more collaborative. Universities are working to better define supervision roles and responsibilities through guidelines, training programs, and recognition of excellent supervisors. Clear communication is important to understand processes and roles.