Can you hear me OK? <a href=" http://www.jasonclarke.net/sports-build-character-essay/#copper ">essay on why you would like to attend a college</a> Should anybody be able to become a teacher then? Not necessarily. There is some evidence that teacher subject knowledge impacts performance positively. But there are many ways to gain subject knowledge, which is probably best determined by diagnostic assessments rather than via crude measures such as degree qualifications. Indeed, an English study from 2012 found no impact at all of degree qualifications on pupil achievement. At the same time, the impact of subject knowledge should not be exaggerated. Most of the variance in teacher effectiveness remains unexplained. For this reason, the diagnostic assessments should only be used to weed out the worst apples.