It is easier to collect data on teachers' qualifications, experience, or training than to get a precise idea of their command of subject matter or their classroom behaviour. However, research consistently shows that "class effect" (the impact on a student of being in one class rather than another) on pupil performance is relatively high, especially in Africa, whereas the impact of qualifications, experience, or training on pupil learning is generally low. The purpose of this paper is to compare teacher academic qualifications and professional training on the one hand, with teacher test scores and behaviour on the other, showing the weak links between the former and the latter. What also emerges is the importance of certain external management-related factors such as the vastly reduced hours of effective learning time due to high rates of absenteeism and delayed term starts. Despite the importance of what really happens in the classroom, it remains difficult to measure the classroom dynamic reliably and accurately.