I too have just looked it up.... and IMO it has to have some merit....

An average student should be able to do fairly well on the Naplan test, even on a "bad" day, and you would need quiet a few to do so so badly it brings the schools rates down. The test is of basic knowledge and understanding. How do they move on to high school, and be expected to do well, if their basic knowledge is bad??

If a school does particularly bad, then I would have to wonder why. I really wouldn't care that it excels in art or sport, if my child came out barely being able to understand very basic english and maths by year 5... thats a problem.

I looked up my kids schools, and wasn't surprised that they rate very well, we picked them for a reason, not just academically. I looked up schools I heard had a bad rep, and ones I know are pretty bad, and yep, REALLY poor results.