The more you work in educational sphere, the stronger you feel the inferiority of group teaching compared to indivisual tutoring. We can ask then: why do people use group instruction? The answer is obvious: to teach each kid or adult individually, you need millions of teachers, which is impossible. Thus, starting with middle ages, children were grouped into classes of 10-30 persons to be taught. Are there any benefits of group training juxtaposed to person-to-person lessons? If we take present days, the only plus seems to be the cost. If you start learning a new skill in a group, you will spend tens of times less money than if you invite a professional tutor or a coach to help you personally. Are there any more advantages to group instruction? I don't see any. Only a skilled teacher alone can instill within a student a proper understanding of a subject and input enough love and care into his disciple. Sometimes people say that within a group you interact with other guys thus developing your social skills and practicing the craft in the society - yes, it is true, but those group meetings can be just added to individual lessons once in a while, and the system will be perfect. If you run some kind of school or courses, try to have individual lessons available to your students. Remember that group sessions of 20-40 students cannot be really effective a priori. You simply don't have an opportunity to learn each student individually. So, your school turns into the conveyor of mediocre individuals production. Whatever art or skill we take: sports, technology, art - only a talented coach can raise a unique specialist. Can you imagine a professional boxer being prepared for his bout for the title of absolute champion of the world, in a group of 20 such like guys?