This is a tried, tested and improved assesment that has worked well with many students.
The assesment is based on the old NC levels 1 to 5 (subdivided into a,b & c)but you can convert into any level description you need, frankly a staged 1 to 5 indicator is as useful as ever whatever you may wish to call it.
I have devised a sytem which gives you a measure of success: each question can score 0, 1 or 2, if a student scores a 2 then you can say they understand the concept fully, score of 1 they understand partially, 0 means they may have experienced the concept but do not understand it much if at all.
The support sheet can be used as a teaching scheme for staff. Split into 3 columns the first column states what concept is being testsd, 2nd column tells you what is required for a score og 1, 3rd column what is required for a score of 2.
I have used this sytem to calculate a score for students...if they achieve 75% or more then I believe you can say they have achieved that level.