To accommodate these requirements, state departments of education commonly use state test scores to
calculate measures of student learning, which we refer to as growth scores or value - added measures.
Despite the smaller (i.e., than for teachers and teaching), yet still significant
measured effects on
student learning for school - based factors beyond the classroom — Hattie has
calculated an effect size
of 0.39 for principals / school leaders [3]-- research evidence has confirmed that «school leaders can play major roles in creating the conditions in which teachers can teach effectively and
students can
learn».