Can you show me where it says this in official BOS literature.
I have been pushing for this at my school for over 10 years and have been told that the BOS says so long as a student is achieving some of the outcomes and completes at least 50% of the number of tasks and weighting of tasks then they are fine. (i.e. 3/5 tasks weighted at 50% or more - which at my school means both exams and one other task!
