What is mastery?
Mastery means a learner has expert knowledge, skills and ability in a subject (or an aspect of that subject) – and they can use and apply it to show a high level of understanding and creativity.
Teaching mastery is about achieving deep, secure learning for all pupils.
It also involves extending the learning of able students by teaching more things on the same topic, rather than accelerating their learning by rapidly moving on to new content.
Read more about mastery on page 17 of the DfE's final report of the commission on assessment without levels.
Mastery doesn't feature in end-of-Key-Stage teacher assessment frameworks
Instead, the Standards and Testing Agency uses the terms "working at greater depth" and "working at greater depth within the expected standard".