"If CAT becomes FDW, what does DOG become?" This is a code question — one of the most common Verbal Reasoning types in the GL Assessment 11+ paper, and one children can turn into a reliable quick win. Codes look intimidating because they mix letters and logic, but almost every one is built from a small number of predictable patterns. Once your child recognises the pattern in the first few seconds, the rest is just careful counting. In Bond's A-to-U labelling of GL question types, letter codes and letter sequences sit close together (broadly the Type M to Type Q family), so the alphabet-hop skill you build here pays off across several question types at once.
Letter codes vs word codes: know which one you are looking at
GL sets two related families. A letter code maps each letter to another letter using a fixed rule (a shift, a mirror, or a position number). A word code gives you several words already coded and asks you to decode a new one, or to code a fresh word, using the same key. GL never tells you in advance which rule a paper uses, so your child's first job is always to diagnose the pattern, not to guess an answer. The good news: the diagnosis takes one matched pair.
The four standard code patterns
Nearly every 11+ code question is one of these four. Teach your child to test them in order.
- Simple shift cipher. Each letter moves by a fixed number forward or backward. If CAT becomes FDW, every letter has shifted +3, so DOG becomes GRJ.
- Mirror/reverse cipher. Each letter is swapped with its alphabet partner (A↔Z, B↔Y, C↔X, and so on). CAT becomes XZG.
- Position cipher. Each letter is replaced by its position number (A=1, B=2, … Z=26). CAT becomes 3, 1, 20.
- Word transformation. The whole word is rearranged: reversed (CAT→TAC), first or last letter dropped, a fixed letter added, or pairs swapped.
A quick-reference table
| Pattern | Rule | Example | Give-away sign |
|---|---|---|---|
| Shift cipher | Move each letter +n or −n | DOG → GRJ (+3) | Same gap between every matched pair |
| Mirror cipher | Swap with alphabet partner | CAT → XZG | Pairs of letters sum to 27 in position |
| Position cipher | Letter → its number | CAT → 3,1,20 | Answer is digits, not letters |
| Word transform | Rearrange the whole word | CAT → TAC | Same letters, different order |
Write the alphabet down first — every time
The single biggest speed gain is a physical alphabet strip. At the very start of the VR section, before reading any question, your child writes A B C D … Z along the top of the scrap paper, and underneath each letter its number 1 to 26. Now shifts become finger-hops along a line instead of mental arithmetic, mirror pairs are visible at a glance, and position ciphers need no counting at all. This one habit removes the most common source of code errors: miscounting past the end of the alphabet, where Z wraps back to A.
Worked example: a shift code
If BUS becomes EXV, what does CAR become? Compare one matched pair: B→E is +3. Check a second pair to be safe — U→X is +3, S→V is +3. The rule is confirmed as +3. Now apply it to CAR using the alphabet strip: C→F, A→D, R→U. The answer is FDU. Notice the discipline: confirm the shift on more than one letter before trusting it, because a single coincidence can send a child down the wrong path.
Worked example: a mirror code
If CAT becomes XZG, what does DOG become? The gaps are not equal (C→X is a big jump, A→Z is bigger), which rules out a shift, so test the mirror: A↔Z, B↔Y, C↔X — yes, C maps to X. Apply the mirror to DOG: D↔W, O↔L, G↔T. The answer is WLT. A neat check is the position rule: mirror partners always add up to 27, so D (4) pairs with W (23), and 4 + 23 = 27.
Timing, SAS and why accuracy pays
GL VR papers are multiple-choice, answered on a separate answer sheet, tightly timed at roughly 35–50 seconds a question. Codes are among the fastest questions to bank marks on once the pattern is spotted, so they are worth protecting time for. Every correct answer feeds the Standardised Age Score (SAS), which converts a raw mark to an age-adjusted score (roughly 69–141, with 100 the average) so younger children in the year group are not disadvantaged. Getting the quick, pattern-based questions right consistently is exactly what lifts a SAS — precision on codes is scoring-literate practice.
Common traps to avoid
- Wrapping the alphabet. A +3 shift on Y is B, not "past Z". The written strip prevents this.
- Confirming on one letter only. Always check the rule on a second pair before applying it.
- Mixing up code direction. Decoding (code → word) reverses the rule you used for encoding.
- Rushing the answer sheet. Fast working is wasted if the bubble lands on the wrong row.
Frequently asked questions
How many code patterns are there really?
Four cover the vast majority of 11+ code questions: shift, mirror, position and word transformation. Learn to test them in that order and almost every question falls quickly.
Does GL tell you which code type a paper uses?
No. GL does not disclose in advance which question types appear, so your child must diagnose the rule each time from a matched pair. That is why the write-the-alphabet-first habit matters so much.
How long should a code question take?
Aim for well under the ~40-second average once the pattern is spotted — codes are meant to be quick wins. Use the time saved on wordier questions such as sentence completion.
Quest Arena's free VR worksheets include code-question drills graded by pattern type, and you can rehearse them under real timing with our mock papers or match them to your target exam using centre-specific mocks. For the wider picture — dates, format and question families — see the exam guides, the GL paper guide and the revision hub.