Our table follows the same principles used in standardised educational and psychological tests:
Centred on 100: This represents the average performance for the population.
Built on 15-point intervals: Each major step (e.g. 85, 100, 115) reflects about one standard deviation — a meaningful statistical difference.
Balanced around the mean: The scale is symmetrical, so “Above” and “Below” ranges mirror one another.
Clear and interpretable: We include finer bands around the average (like High Average and Low Average) so teachers and parents can see smaller differences without over-interpreting them.
Aligned with national standards: These bands match those used by leading test publishers and are designed to make comparisons across different abilities and ages consistent.