What Is the Difference Between a GL Assessment and a Maths Diagnostic?
A GL Assessment measures your child’s aptitude — reasoning ability, spatial awareness, and verbal logic — and compares them against a national norm group using standardised scores where 100 is average. A maths diagnostic assessment measures achievement — what your child actually knows and can do against specific curriculum benchmarks. GL tells you potential; a diagnostic tells you current reality. A child can score well above average on a GL Assessment while carrying significant gaps in fractions, algebra, or problem-solving. Schools across Dubai commonly use GL for Year 4 and Year 6 placement, but these results alone cannot tell you which topics your child needs to work on. For a complete picture, you need both: GL to understand capacity, and a diagnostic to map exactly where the gaps are and what to do about them.
What Is a GL Assessment?
GL Assessment (originally Granada Learning) is one of the world’s largest providers of standardised educational tests. Their products are used in over 100 countries and are the standard in the majority of British curriculum schools in Dubai. The most commonly used GL products include CAT4 (Cognitive Abilities Test), Progress Test in Maths (PTM), Progress Test in English (PTE), and the New Group Reading Test (NGRT).
GL Assessments are designed to measure aptitude and potential rather than what a child has been taught. The maths-related elements of GL tests assess:
- Quantitative reasoning — the ability to manipulate numbers and identify numerical patterns
- Spatial reasoning — mental rotation, pattern recognition, and visual-spatial skills
- Non-verbal reasoning — solving problems using shapes and diagrams without relying on language
- Verbal reasoning — word relationships, logic, and deduction using language
Results are reported as a Standard Age Score (SAS), normalised so that 100 represents the average for a child of that age. A score of 115 places your child in roughly the top 16%, while 85 places them in the bottom 16%. Schools use these scores to make placement decisions, identify children for gifted programmes, and track cognitive development over time.
The critical point for parents: GL Assessments tell you how your child thinks, not what they know. A child with strong reasoning ability may still have significant gaps in curriculum content. For a full breakdown of GL tests used in Dubai, see our GL Assessments guide for Year 4 and Year 6 parents.
What Is a Maths Diagnostic Assessment?
A maths diagnostic assessment is a completely different kind of test. Rather than comparing your child to a norm group, it measures your child’s actual knowledge and skill against specific curriculum benchmarks. It answers questions like: Can your child add fractions with unlike denominators? Do they understand place value to the hundred-thousands? Can they solve two-step word problems involving percentages?
Diagnostic assessments are criterion-referenced, meaning they measure against defined standards rather than against other children. The result is not a single score but a detailed map of strengths and weaknesses across topics and year-level expectations.
A well-designed maths diagnostic typically covers:
- Number and place value — understanding of number systems, ordering, rounding
- Operations — addition, subtraction, multiplication, division across whole numbers, fractions, and decimals
- Fractions, decimals, and percentages — equivalence, conversion, and application
- Algebra — expressions, equations, sequences, and algebraic reasoning
- Geometry and measurement — shape properties, area, perimeter, angles, units
- Statistics and probability — interpreting data, averages, and chance
- Problem solving and reasoning — applying knowledge to unfamiliar contexts
The output is actionable: you know exactly which topics your child has mastered, which are partially understood, and which have been missed entirely. This makes diagnostic assessments invaluable for planning targeted maths tutoring.
Key Differences: Aptitude vs Achievement
The fundamental distinction between GL and diagnostic assessments is the difference between aptitude (capacity to learn) and achievement (what has actually been learned). Both are important, but they answer very different questions.
Think of it this way: a GL Assessment is like measuring engine horsepower, while a diagnostic is like checking which parts of the engine need servicing. Both readings are useful, but they tell you completely different things.
Why Your Child Might Score Well on GL but Still Have Maths Gaps
This is one of the most common scenarios we see in families across Dubai, and it confuses many parents: a child comes home with an above-average GL score, yet they are clearly struggling with maths homework, falling behind in class, or getting disappointing test marks.
There are several reasons this happens:
- GL tests reasoning, not curriculum content. A child with excellent pattern-recognition and logical thinking will score well on the quantitative reasoning section of a CAT4, even if they have never been properly taught long division, fractions, or algebraic expressions. The GL score reflects their capacity to learn maths, not whether they have actually learned it.
- Teaching gaps are invisible to GL. If a child missed key topics due to a school move, teacher absence, the pandemic period, or simply a bad term, those gaps will not show up on a GL Assessment. The test does not cover curriculum-specific topics.
- Confidence and application are separate from reasoning. A child may be a strong abstract thinker but freeze when faced with multi-step word problems, lack confidence in exam conditions, or struggle with maths anxiety. GL scores do not capture these factors.
- The mismatch can actually increase over time. High-aptitude children who have underlying gaps are often placed into higher sets or more demanding streams based on their GL scores. This means they face harder content while still carrying foundational gaps — a recipe for growing frustration.
If your child has a strong GL score but is not performing as expected in maths, the answer is almost always the same: they need a diagnostic assessment to find out exactly where the gaps are.
Free Maths Diagnostic — Find Your Child’s Gaps in 15 Minutes
Our free Learning Gaps Assessment pinpoints exactly which maths topics your child has mastered and which need attention — no GL score required. Get a personalised results breakdown with year-level benchmarks and next-step recommendations.
Take the Free Assessment →When Each Assessment Is Most Useful
Both GL Assessments and diagnostics have their place. Understanding when each is most valuable helps you make better decisions as a parent.
GL Assessments Are Most Useful When:
- Your child is approaching a school transition — Year 4 or Year 6 in British curriculum schools, or applying for selective secondary places. GL scores are a key part of admissions decisions.
- You want to understand your child’s cognitive profile — Are they stronger in verbal or non-verbal reasoning? Is their quantitative reasoning significantly higher or lower than their other scores? This helps you understand how they learn.
- The school is making streaming or set decisions — GL results, particularly CAT4, are used to allocate children to ability groups. Understanding the scores helps you advocate for your child if you believe the placement is wrong.
- You are comparing potential against performance — A significant gap between GL aptitude scores and classroom achievement is a red flag that something is not being addressed.
Diagnostic Assessments Are Most Useful When:
- Your child is struggling in a specific subject — You need to know which topics are causing the problem, not just that there is a problem.
- You are starting tutoring — A diagnostic gives the tutor a precise starting point. Without it, tutoring sessions can waste weeks on topics your child already understands.
- Your child has changed schools or curricula — Moving between British, IB, American, or year-level expectations often creates hidden gaps. A diagnostic finds them.
- You want to track improvement over time — Running a diagnostic before and after an intervention period shows exactly what progress has been made.
- Your child scores well on GL but underperforms in class — This is the strongest signal that a diagnostic is needed. The aptitude is there; the knowledge is not.
How to Use Both Together for a Complete Picture
The most informed parents in Dubai use GL results and diagnostic data together. Here is how to combine them effectively:
- Start with the GL results you already have. Most British curriculum schools send home GL or CAT4 reports at least once during primary school. Find these reports and note the Standard Age Scores. Pay particular attention to the quantitative reasoning score — this is the most relevant measure for maths aptitude.
- Run a diagnostic to map current knowledge. Use a criterion-referenced diagnostic (like our free Learning Gaps Assessment) to identify exactly which topics your child has mastered and which have gaps.
- Compare aptitude against achievement. If your child has a quantitative reasoning SAS of 110+ (above average aptitude) but the diagnostic shows gaps in topics expected at their year level, there is clear underachievement. This child has the capacity to do well but has not yet been taught effectively or has missed critical building blocks.
- Use the diagnostic to plan intervention. The GL score tells you the ceiling — what your child is capable of achieving. The diagnostic tells you the floor — where they currently are. The gap between them is the work that needs to be done, and the diagnostic tells you exactly where to start.
- Repeat the diagnostic after intervention. After a period of targeted maths tutoring, run the diagnostic again to confirm gaps have been closed and new topics have been consolidated.
This combination is far more powerful than either test alone. GL tells you the destination your child is capable of reaching. The diagnostic tells you the route from where they are now.
Our Free Diagnostic: What It Covers and How to Use the Results
GetYourTutors built our free Learning Gaps Assessment specifically for Dubai parents who want clear, actionable information about their child’s maths level. Here is what it covers and how to get the most from it:
What the Assessment Covers
- Year-level aligned questions — Select your child’s current year level and the assessment adapts to test the topics they should have mastered by that stage
- Core curriculum topics — Number, operations, fractions, decimals, percentages, algebra, geometry, measurement, and statistics
- Progressive difficulty — Questions start at the expected level and increase in complexity to find the boundary between confident knowledge and gaps
- Time-efficient format — Approximately 15 minutes to complete, so it does not feel like another exam for your child
How to Use the Results
After completing the assessment, you receive a personalised results breakdown showing:
- Which topics your child answered correctly and confidently
- Which topics showed partial understanding (got the easy parts but not the harder applications)
- Which topics were missed or answered incorrectly, indicating a gap
- A recommended focus order for addressing gaps, starting with the most foundational topics
If your child’s school has provided GL or CAT4 results, compare them with the diagnostic output. If the GL score suggests above-average aptitude but the diagnostic reveals gaps, your child is likely underachieving and would benefit significantly from targeted support.
For families who want expert help closing those gaps, GetYourTutors' in-home maths tutors use diagnostic results as the starting point for every tutoring programme. No time is wasted re-teaching topics your child already knows — every session targets the specific areas that need attention.