Visible teaching and learning occurs when learning is the explicit goal, when it is appropriately challenging, when the teacher and student both seek to ascertain whether and to what degree the challenging goal is attained, when there is deliberate practice aimed at attaining mastery of the goal, when there is feedback given and sought, and when there are active, passionate and engaging people participating in the act of learning” (p. 22).
Hattie also convincingly argues that the effectiveness of teaching increases when teachers act as activator instead of as facilitator. He developed a way of ranking various influences in different meta-analyses related to learning and achievement according to their effect sizes. In his ground-breaking study “Visible Learning” he ranked 138 influences that are related to learning outcomes from very positive effects to very negative effects. Hattie found that the average effect size of all the interventions he studied was 0.40. Therefore he decided to judge the success of influences relative to this ‘hinge point’, in order to find an answer to the question “What works best in education?”
Ivo Arnold, 2011. Book Review: John Hattie: Visible learning: A synthesis of over 800 meta-analyses relating to achievement, Int Rev Educ (2011) 57:219–221, DOI 10.1007/s11159-011-9198-8, Routledge, Abingdon, 2008, 392 pp, ISBN 978-0-415-47618-8 (pbk)
Hattie Ranking: 195 Influences And Effect Sizes Related To Student Achievement available here