Shape codes is one of the standard non-verbal reasoning patterns in GL-style 11+ papers, and it is one of the most learnable. Each shape in a small group carries a two-letter code, and your child has to work out what each letter stands for, then apply the same rule to code a brand-new shape. NVR rewards method over raw talent more than almost any other 11+ subject: children who learn to interrogate shapes systematically routinely overtake ‘naturally spatial’ peers who guess. This guide gives you the exact method, a worked example, the classic traps, a timing budget, and free practice to build the habit.
What a shape codes question looks like
You are shown three, four or five shapes, and each one has a two-letter code printed beneath it, for example AX, BX, AY. Then a fresh test shape appears with no code, and five answer options (A to E) each offer a possible code. Your child must decode the rule and pick the correct label. In GL Assessment papers this sits inside the multiple-choice NVR test, answered on a separate answer sheet by pencilling the matching bubble. In reasoning-heavy regions such as Lincolnshire, NVR carries a large share of the total marks, so getting confident with shape codes genuinely lifts a Standardised Age Score.
Shape codes belong to the wider family of GL NVR types. If you want the full map of matrices, series, rotations, reflections, analogies and nets, our every NVR question type explained post lays out the whole territory in one place.
The method, step by step
The reliable approach is to treat the first letter and the second letter as two completely separate rules. Never assume the first letter controls the same property in every question — it changes from question to question, and the paper never tells you which property it is.
- Group by the first letter. Find every shape that shares the same first letter and ask: what do they have in common that the differently-lettered shapes do not? That shared property is what the first letter encodes — it might be number of sides, shading, size, or line thickness.
- Group by the second letter. Repeat the exercise for the second position. It will encode a different property entirely.
- Write the key. On scrap thinking, note something like “first letter = colour, second letter = size”. This tiny key prevents the most common slip.
- Code the test shape. Read the two properties off the new shape, match each to its letter, and select that pair from the options.
- Check both letters. A tempting wrong answer usually gets one letter right and one letter wrong, so verify each position before you commit.
A fully worked example
Suppose the examples are: a small black triangle coded AX, a large black triangle coded BX, and a small white triangle coded AY. Compare the two “A” shapes: both are small, so A = small and by elimination B = large. Compare the two “X” shapes: both are black, so X = black and Y = white. Now a test shape appears — a large white triangle. Large gives us B; white gives us Y; the answer is BY. Notice the shape being a triangle never mattered: it was a red herring, held constant across every example on purpose.
The classic traps
- Assuming letter position maps to a fixed property. The first letter is not always “the shape” and the second is not always “the colour”. Re-derive the key every single time.
- Ignoring a third property that varies freely. Some shapes differ in a feature the code does not track (a decoy). Focus only on the properties the letters actually separate.
- Stopping after one letter. If two answer options share a first letter, the second letter is doing the work — check it.
- Confusing shading with size, or orientation with reflection. Decide which single attribute is changing before you name it.
The attributes to scan
Shape codes always hinge on a small set of visual attributes. Teaching your child to run this checklist turns guessing into deduction.
| Attribute | What to look for |
|---|---|
| Number of sides / elements | Triangle vs square; one dot vs two |
| Shading / fill | Black, white, striped, dotted |
| Size | Small vs large vs medium |
| Orientation | Pointing up, down, left, right |
| Position | Element top, bottom, inside, outside |
| Line thickness | Thin outline vs bold outline |
| Symmetry | Mirror-symmetric or not |
Timing and pacing
GL NVR papers run at roughly 35 to 50 seconds a question, so a shape codes item deserves about 40 seconds: ten to build the key, twenty to code the test shape, ten to check both letters. If the key is not clear within the first fifteen seconds, mark the question, move on, and return — a skip-and-return plan protects easy marks later in the paper.
| Stage | Target time |
|---|---|
| Build the first-letter and second-letter key | ~15 sec |
| Code the test shape | ~15 sec |
| Check both letters against options | ~10 sec |
How the score works
NVR raw marks are converted to a Standardised Age Score (SAS), typically on a scale from about 70 to 140 with 100 as the average. The score is adjusted for your child’s exact age in months, so a younger child is not disadvantaged against an older classmate. Getting the trickier code questions right nudges the raw score up, which lifts the SAS — and many grammar schools look for roughly 111 or above, though exact qualifying marks vary by area and year.
How to practise this type
Do shape codes in short, focused bursts — ten questions, mark them, then review every error out loud (“which property did I miss?”). That parent-coaching step matters more than volume: a wrong answer tells you exactly which attribute your child overlooked. Our free NVR worksheet sets isolate each pattern one at a time, the full NVR types list maps the whole paper, and timed mock papers knit the types back together at real exam pace. For a broader plan, the revision hub sequences reasoning practice from Year 4 foundations to Year 6 timed mocks, and the GL 11+ papers guide explains the exact format your child will face on the day.
Frequently asked questions
Does the first letter always mean the same thing?
No. The property each letter encodes changes from question to question, and GL never tells you in advance. Always re-derive the key by comparing shapes that share a letter.
How long should a shape codes question take?
Aim for about 40 seconds. GL NVR papers allow roughly 35 to 50 seconds per question, so if the rule is not clear quickly, skip and return rather than burning time.
What score does my child need?
NVR is standardised into an age-adjusted SAS, usually between 70 and 140. Many grammar schools look for around 111 or higher, but exact pass marks differ by region and year, so check your target school’s guidance.