Donald C. Orlich in his review at Education News sums it up nicely:
"[T]wo conclusions may be inferred: (1) Teacher quality is a key link to student achievement and (2) Most current educational reform efforts have simply been “fads.”We have been arguing for years for an evidence-based approach to education, learning, teaching, and the arts and sciences in general, and John Hattie's work is an exclamation point in this direction.
This book is a MUST reading for all involved in teacher education programs, those who determine educational policies and standards, and school evaluators."
Hat tip to CZ/CK and a German-language Zeit Online article titled Ich bin superwichtig! by Martin Spiewak about the John Hattie evidence-based education study.