Notes:

 I have argued elsewhere that any assessment principle could be more or less empowering depending on how it was implemented (that is it could slide up or down the engagement-empowerment dimension). For example, a teacher might ‘clarify what good performance is’ (principle 1) by providing students, in advance of an assignment, with examples of the kind of work required (e.g. some examples of essays from previous student cohorts).
Alternatively, the teacher might organise a session where students are required to examine these essay examples to identify which is better and why. The second approach would usually be more supportive of the development of learner self-regulation than the first because the student would be more actively engaged in constructing, internalising and owning some assessment criteria. The important point is that if students are given a active and responsible role in the implementation of a principle, then this is more likely to develop learner self-regulation).
Note that the most empowering scenario might be where students feel able to organise their own active engagement with criteria and even question their appropriateness or validity.
So this dimension captures the idea that although teachers must create academic structures that involve and engage, they also need to develop ways of sharing responsibility for learning with students. Another way to view this dimension is that it depicts the progressive reduction of teacher ‘scaffolding’.