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What is the Standard Age Score (SAS) and why is it recommended for comparing reading assessment results across students?
The Standard Age Score (SAS) is the score recommended by GL Assessment when making comparisons across any norm-referenced test. It shows how a student is performing relative to the national average in an age-adjusted way — making it the fairest possible basis for comparing results from tests like the NGRT and CAT4 across different cohorts. When the goal is to understand where a student truly stands, the SAS is the right metric to use.
A norm-referenced test ranks a student's performance against a representative national sample. Rather than measuring against a fixed pass mark, it shows how a student compares to peers of the same age — which is exactly what the SAS is designed to express.
The distinction matters in practice. Two students sitting the same NGRT reading test may achieve the same raw score yet be of different ages. Without age-adjustment, that shared score conceals a real performance gap. The SAS eliminates that distortion, making cross-cohort comparisons meaningful rather than misleading.
This is a point explored directly in Education: Joining the Dots, where Georgina Cook highlights the SAS as the correct unit of comparison when using GL Assessment tools for student transition work.
The metric that makes CAT4 and NGRT results speak the same language
The SAS becomes especially powerful when combining data from two different instruments — as when schools use both the CAT4 (Cognitive Ability Test 4) and the NGRT (New Group Reading Test) together during transition. Both assessments produce a Standard Age Score, which means their results can be placed on a shared, comparable scale.
This is what makes discrepancy analysis possible. In this episode, GL Assessment describes five discrepancy categories between CAT4 verbal reasoning and NGRT reading scores: the expected middle 50%, a higher or lower band covering the next 15% on each side, and a much higher or much lower band covering the top and bottom 10%. None of that analysis would be valid without a common, age-adjusted score — the SAS.
For schools like those in Laidlaw Schools Trust, where some settings have over 60 languages spoken by pupils, the age-adjusted nature of the SAS is particularly valuable. It avoids penalising students whose reading development may reflect linguistic background rather than cognitive ability.
"Don't wait until a child is failing to act. You need to diagnose on entry, involve staff from the start, and if you're fortunate enough to have digital tools that you can access, align that to your transition work, because it can be transformational."
Talia Caralambos — Director of English, School Improvement Team, Laidlaw Schools Trust.
Talia Caralambos relocated to the North East in April after training and teaching English and Media at Ritchie Diver Secondary School in London. She comes from a bilingual household and taught English in India at age 17 — an experience she credits with sparking a lifelong commitment to equity and education through literacy. As Director of English at Laidlaw Schools Trust, she oversees curriculum development and literacy improvement across 11 schools serving communities with high mobility, economic disadvantage, and over 60 languages spoken in some settings. Her work puts diagnostic assessment data — including SAS-based comparisons — at the centre of transition planning.
Why early, SAS-based diagnosis changes what teachers can do in September
Laidlaw Schools Trust administers the NGRT to Year 6 pupils over a three-week window in May and June, with all diagnostic data available by mid-June — well before the September secondary school start. That timeline is deliberate. SAS-based results give secondary teachers a clear picture of each incoming student's reading level before they ever meet them.
The SAS makes that picture honest. It doesn't flatten differences between students of different ages, and it doesn't reward older students simply for being further along developmentally. Teachers can act on what the data actually shows — as discussed in detail in this episode of Education: Joining the Dots.
Caralambos is explicit on this point: early, accurate diagnosis using the right scoring framework is what separates reactive intervention from genuinely proactive transition support. The SAS is the scoring framework that makes that diagnosis reliable enough to act on.
See also
How can CAT4 and NGRT be used together to support student transition and identify underachievement?
Georgina Cook and Emma Dibden explain that combining CAT4 verbal reasoning scores with NGRT reading results allows educators to compare a student's reading performance against their cognitive potential, revealing underachievement that raw scores alone would miss.
What advice do transition programme leaders give to educators building their own primary-to-secondary literacy transition plan?
Graeme Finlay advises careful liaison with GL Assessment over several months to design a reading strategy before identifying tools, and stresses the importance of involving all staff from the outset rather than leaving implementation to a single champion.
What is the 'six-week dip' in the context of student transition, and how do these trusts address it?
The 'six-week dip' refers to the period after summer where students readjust to school routines and may lose academic momentum, particularly in reading. Both Laidlaw Schools Trust and Bishop Wilkinson Catholic Education Trust use early diagnostic assessment data — including SAS-based results — to identify vulnerable students before this dip takes hold.
Key takeaways
- The Standard Age Score adjusts for age, making it the only fair basis for comparing reading results across students of different ages in the same cohort.
- GL Assessment recommends the SAS as the standard unit of comparison across all its norm-referenced tests, including the NGRT and CAT4.
- Using a shared SAS scale is what enables meaningful discrepancy analysis between a student's cognitive ability and their reading performance.
- Schools that collect NGRT data in May and June, reported as SAS, give secondary teachers actionable insight before the school year even begins — as explored in Education: Joining the Dots.
This answer comes directly from a real episode of Education: Joining the Dots. Hear the full conversation on Listenly.
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