Rox88, if you're coming last in assessments and come first in the exam, you will:
-Receive, as your assessment mark, the lowest external exam mark for your class
-Receive, as your exam mark, the mark you actually got in the exam.
You always keep your exam mark, but your assessment mark will be the exam mark for your class corresponding to your assessment rank.
Example:
Raw marks-
Exam Assessment
Tom 85 72
Dick 91 54
Harry 87 43
T, D and H keep their exam marks. Tom has the highest assessment rank, so Tom will receive as his assessment mark the top exam mark for the class (Dick's, 91). Dick was second in assessments, so he will receive the second exam mark (Harry's, 87) as his assessment mark. Harry was bottom of assessments, so he will receive the bottom exam mark (Tom's, 85) as his assessment mark.
So, the moderated results will be:
Exam Assessment
Tom 85 91
Dick 91 87
Harry 87 85
So T, D and H have preserved their assessment rank. However, note that the class averages for exam and assessment are now the same, which evens out differences between assessment schemes from school to school. (In this case, it appears that the school's assessment scheme was very harsh, as T, D and H got much lower assessment marks than exam marks, so they moderate upwards to match their exam marks.)
But really, it's best not to worry about the system. Just do your best in all assessments and exams and the system will work fine.
EDIT: Whoops, those tables didn't work very well. The columns go Name/Exam mark/Assessment mark.
EDIT2: On rereading, perhaps not the best explanation I've ever given. The gist is there.