One test cannot tell one about a student's education level. For example, someone may find NAPLAN questions hard, while they find ICAS ones easy. This means that just ONE NAPLAN test cannot explain everything. Also, the student may not have been feeling well on the day of the test. So how would one be able to know a child's growth measure through a single test?! I say that it would be silly to think that one test could prove any student's level.