Validation is similar to mattering. The practitioner ensures that clients feel that they are important to the process and that their experiences, thoughts, and feelings are valued by the practitioner.
Walters, Beverley, Blythe C. Shepard and Priya S. Mani, “Developing Effective Client Relationships.” In Blythe C. Shepard and Priya S. Mani (editors). Career Development Practice in Canada: Perspectives, Principles and Professionalism. Toronto: Canadian Education and Research Institute for Counselling (CERIC), 2014, p.169.