Dirk Zimmermann illustrates that some therapists significantly differ concerning their average dropout rates. He points out that initial impairment is a strong predictor of early termination. Different dropout criteria as well as various explaining variables on patient and on therapist level were assessed. Premature treatment termination is a common phenomenon in psychotherapy with mean dropout rates of about 20%. Therapist effects account for 3%–4% of the variation in dropout.  Contents Brief Symptom Inventory Therapist Effects Common Phenomenon in Psychotherapy Multilevel Logistic Regression Assessment for Signal Clients (ASC)  Target Groups Researchers and students of clinical psychology and psychotherapy Teachers and practitioners in psychotherapy and supervision   The Author Dirk Zimmermann studied psychology in Osnabrück (Germany), Bergen (Norway) and Trier (Germany). He works as a research associate at the department of clinical psychology and psychotherapy at the University of Trier since 2014. In addition he is a psychological psychotherapist in training.