Gabriel H Sahlgren disputes whether teaching qualifications affect student performance and outcomes. In 37 years of teaching in a range of mainstream and special schools, I've found a difference in impact between subject-specialist knowledge and "teaching qualifications": the two are not the same. The effect of the latter on the former is open to discussion.
What is significant, and what does make a really positive difference to student engagement and attainment, is the natural ability of a teacher to relate to and communicate with young people. This skill set, when taken together with thorough, up-to-date subject knowledge, is the mark of a truly effective teacher.
Garry Freeman, Leeds.