More than one million students across Australia are putting their reading, writing and maths skills to the test as part of NAPLAN.
Pupils in years 3, 5, 7 and 9 at almost 10,000 campuses will take part in the annual assessments designed to inform education structures from Wednesday.
It's the first time the tests are being conducted in March instead of May, with the hope results will inform teaching and learning programs for the rest of the year.
But education experts have criticised the new schedule, which sees the test taking place just over halfway into first term.
It's too early in the school year to know whether students are effectively learning concepts taught at their year levels, according to Dr Venesser Fernandes, a lecturer in educational leadership studies at Monash University.
"For students already suffering multiple learning and social disadvantages, the test timing could contribute to low self-esteem when it is likely their results will fall in the lower two levels (of assessment)," she said.
"Even though the tests are done online, the time taken for the test results to be prepared remains the same and this holds the biggest disadvantage for the student and the parent."
Dr Fernandes said NAPLAN tests would be better held at the end of the year, giving students more time to absorb knowledge.
This year, there will also be a change to how results are reported, with the 10-grade structure used in previous years simplified to four.
Given these changes, it will be important for state and territory governments to ensure results can be compared to previous years, said Queensland Liberal National Party education spokesperson Christian Rowan.
David de Carvalho, of test regulator Australian Curriculum, Assessment and Reporting Authority, emphasised the need to keep the test in perspective and encouraged students not to feel apprehensive about it.
