University outpatient clinics are important facilitators of psychological treatments for children, adolescents, and adults with diverse mental disorders and are important contributors to psychotherapy research in Germany. Since 2013, a steering committee has initiated and realized a project aiming to coordinate research efforts in these clinics. In 2016, unith. ev, a network of university training centers for psychotherapy, took over the sponsorship of this project. The main goal of the project is to aggregate and analyze longitudinal treatment data - including patient, therapist, and treatment characteristics - across all participating outpatient clinics. The start of data assessment is planned for 2018. This paper describes legal, methodological, and technical challenges, the current state of the project, as well as a pilot study planned for 2017.