“Efficacy is a belief about one’s own ability (self-efficacy) or the ability of one’s colleagues collectively…to perform a task or achieve a goal (Leithwood & Louis 2012, p. 108).
“The most powerful underlying source of efficacy is having “mastery experiences…when people have opportunities to develop the capacities needed to grapple productively with the challenges they face, their sense of self confidence or efficacy grows significantly” (p. 135).