The numeracy and reading sections compare student performance to proficiency scales that describe expected student performance, based on the number of years of schooling. A proficiency scale for writing ability is not, however, currently available, although one will be created and the PILNA 2021 writing results will be compared to it.

For now, the average writing performance in PILNA 2021 is compared to writing performance over previous PILNA cycles. This gives an indication of writing performance over time, but it does not show whether writing performance is at the level Pacific stakeholders expect it to be.

As shown in theyear four writing performance, the average writing score for year four students in Cook Islands has decreased by 20 points from 2015 but has seen a slight increase from the 2018 PILNA cycle. The average writing score for a year four student in 2015 was 508.71 (SD = 67.27), in 2018 it was 484.39 (SD = 91.73), and in 2021 it was 492.17 (SD = 45.20). With year four girls scoring higher on average than year four boys in writing performance in 2015, 2018 and 2021, girls are more likely to be meeting writing performance expectations than are boys.