Failure of students is rarely the educator's fault, so I'm not quite sure I get your clarification that "educators will seldom lose >20% of students." Students are responsible for whether they succeed or not. A good student will succeed in spite of poor instruction not because of average or excellent instruction. If you routinely lose a lot of students then there are a variety of possibilities -- it could be your teaching style, it could be the course materials or textbook, it could be the students (i.e., lack of screening/necessary prerequisite skills and/or coursework and/or aptitude), etc. Obviously, there is a problem, yes; however, in EMS education I wonder if the problem might be more of a systemic one than one with the educators themselves, although the educators themselves may be disadvantaged systemically by their own training as educators.