If your child is sitting for an independent senior school, there is a strong chance the first hurdle will not be a familiar paper test but the ISEB Common Pre-Test — an online, adaptive, multiple-choice assessment taken in Year 6 (occasionally Year 7). More than 70 leading independent schools, including Eton, Harrow, Westminster, St Paul's and Wellington, use it as a shared first sift. Because it is sat on-screen and adjusts to your child's answers, it feels very different from a printed grammar-school paper. This guide explains exactly what the Common Pre-Test covers, how the adaptive format actually works, and how to prepare calmly and effectively.
What the ISEB Common Pre-Test is
The Common Pre-Test is produced by the Independent Schools Examinations Board (ISEB) and delivered online. Its purpose is to give independent schools an early, standardised snapshot of a child's ability so they can make offers — or invite a child to the next stage — well before Common Entrance at 13+. A key selling point for schools is that a child normally sits the test once, and the result is shared with every participating school the family has applied to. That removes the need to sit near-identical tests at four or five different schools.
It is closely tied to the London 11+ Consortium, a group of well-known London independent schools that use the pre-test as a common entry assessment. Outside London, many boarding and day schools use the same test on their own timetables.
The four sections
The test assesses the same four skill areas that run through the whole 11-plus world. If those areas are new to you, our overview of the four subjects of the 11-plus is a good starting point.
- English — comprehension, grammar, spelling and vocabulary in context.
- Mathematics — number, calculation, fractions, measures, shape and simple problem-solving.
- Verbal Reasoning (VR) — word-based logic: analogies, odd-one-out, letter and number sequences, and vocabulary-led puzzles.
- Non-Verbal Reasoning (NVR) — visual logic: series, matrices, rotations, reflections and spatial patterns.
Content is pitched at roughly the Year 5 curriculum ceiling, so pupils are not tested on material they have not yet met. That said, VR and NVR sit largely outside the national curriculum, so they usually need dedicated familiarisation. Our free worksheets and the non-verbal reasoning guide cover the exact question types your child will meet.
How the adaptive format works
This is the feature that most surprises parents. The Common Pre-Test is adaptive: the difficulty of each question responds to how your child is doing. Answer several questions correctly and the software serves harder ones; slip up and it eases back. This lets the test measure ability efficiently, using fewer questions than a fixed paper would need.
Two consequences matter enormously for preparation:
- Questions cannot be revisited. Once your child moves on, there is no going back to change an answer. Habitual "I'll come back to that one" tactics do not work here.
- Harder questions are a good sign, not a warning. If the test starts feeling tough, it often means your child is doing well and the system has climbed the difficulty ladder. Children need to be told this in advance so they do not panic mid-test.
The whole assessment takes around 2.5 hours, usually with the four sections delivered in a set order and short breaks between them. Schools can arrange for pupils to sit it at their own school, at the senior school, or sometimes at home under supervision.
ISEB compared with the other boards
Parents often juggle an independent-school pre-test alongside a grammar-school entry test, which uses a different board entirely. The table below shows where ISEB sits. For the grammar-school side, see our comparison of GL vs CEM.
| Board | Format | Subjects | Answer type | Prep focus |
|---|---|---|---|---|
| ISEB Common Pre-Test | Online, adaptive | Eng, Maths, VR, NVR | Multiple-choice | On-screen practice, no-going-back discipline |
| GL Assessment | Paper, fixed | Varies by region | Multiple-choice / standard | Question-type drilling, speed |
| CEM (now online) | Online (paper 11+ ended 2023) | Blended | Multiple-choice | Wide vocabulary, timing |
| CSSE (Essex) | Paper, written | Eng + Maths only | Written answers | Written technique, creative writing |
Current state, 2026: a lot of older advice online still describes CEM's separate paper 11+, which was discontinued around 2023. Most former CEM grammar regions now use GL. The ISEB pre-test, by contrast, has been online for years — so treat any guidance that calls it a "paper" as out of date.
How results are used
Scores are age-standardised, meaning a younger, summer-born child is not disadvantaged against an autumn-born classmate: the software adjusts for age in months so children are compared fairly. A standardised score places each child on a common scale (100 is the average), and schools set their own thresholds. Crucially, the pre-test is usually a first stage. A strong result typically leads to an interview, a written assessment, or a place at the senior school's own later exam — it rarely secures an offer on its own.
Never assume a fixed "pass mark". Each school interprets results in the light of its own applicant pool, so the same score can open doors at one school and not at another.
How to prepare
Preparation for an adaptive online test differs from cramming for a paper exam. The goal is secure fundamentals plus screen confidence.
- Build the core skills first. Strong comprehension, quick mental maths and a broad vocabulary underpin every section. Our vocabulary roots guide and word-problems method target two of the biggest score-movers.
- Practise on a screen. Reading and reasoning on a monitor is a different skill from working on paper. Use our on-screen worksheets and timed mocks so the format is familiar.
- Drill the "commit and move on" habit. Because answers cannot be revisited, train your child to make a confident best choice and let it go, rather than agonising.
- Cover VR and NVR deliberately. These are the least school-taught areas. Work through the NVR guide and pattern-based revision exercises.
- Keep maths sharp. A quick recall of key facts helps enormously; our maths formula sheet and area and perimeter guide cover common test topics.
Above all, protect your child's confidence. Short, regular sessions beat long, stressful ones, and a calm child reads an adaptive test's rising difficulty as a challenge rather than a threat.
Registration and timing
Timelines vary by school, so always check each school's admissions page and the key dates hub. As a rough guide, families register in the autumn or spring of Year 6 (some schools test in Year 7), the test window falls across the autumn and winter of the entry year, and the result feeds directly into that school's next admissions stage. Since one sitting is shared across participating schools, coordinate your applications early so every target school is included.
Frequently asked questions
How long is the ISEB Common Pre-Test?
Around 2.5 hours in total, split across four sections — English, Maths, Verbal Reasoning and Non-Verbal Reasoning — usually with short breaks between them.
Can my child go back and change an answer?
No. The test is adaptive, so once a question is answered and the child moves on, it cannot be revisited. Practising a confident "choose and move on" approach is essential.
Does my child sit the ISEB test at every school separately?
Usually not. A child normally sits the pre-test once and the result is shared with all participating schools the family has applied to, which is one of the format's main advantages.