Very good or exceptional?
Our examiners are asked to comment on the quality of the thesis, and give a rating on a 6-point score ranging from 1 = Exceptional through to 6 = Flawed. A score of 2 is Excellent ("strongly competitive at international levels, with fewer than 20% of candidates in this band") and 3 is Very Good ("An interesting, sound and compelling thesis, with approximately 30% of candidates in this band").
Here's how one examiner justified the given grading:
"To place the thesis in the range of theses I have examined, as requested by the University of WA, I rate it as a very good thesis rather than an exceptional one. The concept is simple and the experimental design, once agreed to, could be carried out by most competent researchers. The work is important for the operational field to which it speaks but the techniques are all standard and are applied in a standard way. The analysis is also competent, providing new information rather than new insights. That said, the sheer amount of work is impressive and its applied value beyond question."