ABSTRACT

As noted in Chapter 3, the current mantra, that teachers make the difference, is misleading. Not all teachers are effective, not all teachers are experts, and not all teachers have powerful effects on students (this is what is meant when it is claimed that the “variance due to teachers” makes the difference! It is teachers’ variability in effect and impact that is critical). But there is no doubt that nearly all teachers are effective (that is, if we mean having positive achievement effects, d > 0.00) and many can have an effect above the hinge-point in the “zone of desired effects” (d > 0.40). The important consideration is the ways that teachers differ in their influence on student achievement-what it is that makes the most difference?