Expertise can usually be proven with official qualifications and/or certificates confirming that coaches have, for example, completed professional coaching training. They also hold a degree in the humanities, the natural sciences, the social sciences or in business administration. In addition to these formally verifiable competences, coaches can explain, justify and develop the philosophical background to inform about their way of coaching. Quality coaches have normally had a good to very good general education, so that they can explain and apply fundamental sociological, pedagogical, psychological, economic and legal concepts. And they can evaluate and apply insights from coaching research.