NAPLAN (National Assessment Program – Literacy and Numeracy) is a standardised test. It measures specific literacy and numeracy skills at a specific moment.
It's NOT an IQ test. It's NOT a complete picture of your child's ability. It's one data point.
Tests are Year 3, 5, 7, 9. They assess: reading, writing, spelling, grammar, and numeracy. That's it.
A NAPLAN score tells you: does your child meet the national minimum standard? Where do they sit relative to peers? That's useful, but limited.