My kids are not in school yet so forgive my so-called ignorance. However, my understanding is that the Myschool website allows you to compare like with like, taking into account the socioeconomic background and other factors such as special needs kids.

The NAPLAN scores obviously don't take that into account but the Myschool website does and allows you to see how a school rates per se then how it rates against similar schools.

I have no idea what people used to do to compare schools before NAPLAN and the Myschool website. Perhaps you would care to fill me in, unless that was meant to be a rhetorical question. Wasn't that why Julia Gillard pushed so hard to introduce it - so that parents could compare. Obviously any test is flawed, but it does allow you to have a bit of a clue.