ISEB Common Pre-Test: the Independent School 11+ Explained
· 9 min read
How independent senior schools assess at 11+: the ISEB Common Pre-Test, CAT4 and interviews, how they differ from grammar 11+ exams, and how to prepare.
Independent school admissions work differently from grammar 11+
Parents who have read about the grammar-school 11+ often assume independent senior schools work the same way. They usually do not. Where a grammar test is a single, high-stakes paper administered by a local authority or consortium, independent schools typically assess through a combination of elements: an online reasoning and attainment test (most commonly the ISEB Common Pre-Test), one or more interviews, a report or reference from the child's current school, and sometimes a school-specific written exam or taster day. No single element decides the outcome; schools build a rounded picture. The timing differs too — independent assessments often run on their own calendars, with some screening happening in Year 6 and conditional offers confirmed later. If you are weighing selective state and fee-paying routes side by side, our guides on independent versus grammar schools and the 11+ versus Common Entrance set out the trade-offs; this guide focuses on the assessments themselves.
What is the ISEB Common Pre-Test?
The ISEB Common Pre-Test is an online, multiple-choice, age-standardised assessment used by a large number of independent senior schools as a first-stage screen. It covers four areas that will look familiar to any 11+ family: English, Mathematics, Verbal Reasoning and Non-Verbal Reasoning. It is adaptive in the sense that it is standardised for age, and it is designed to be taken once and shared securely with several schools, sparing children from sitting near-identical tests repeatedly. It is usually administered at the child's current school under supervised conditions, and can often be taken in sections rather than one long sitting. Historically associated with 13+ pre-testing, it is increasingly used at the 11+ entry point as well — but exactly when a given school uses it, and what weight they place on it, varies, so always check each target school's admissions page for its specific timetable and requirements. The headline for parents is that the four sections map almost exactly onto the four classic 11+ subjects, which means most grammar-oriented preparation transfers directly.
How does CAT4 fit in?
Some independent schools — and some state schools for internal setting — use CAT4, the Cognitive Abilities Test from GL Assessment, either instead of or alongside an attainment test. CAT4 measures reasoning across four areas: verbal, quantitative, non-verbal and spatial. Unlike a maths or English paper, it is intended to gauge underlying learning potential rather than taught knowledge, and it is often described as 'not coachable'. That description is only half true: you cannot revise content for CAT4 the way you revise fractions, but familiarity with the question formats, the on-screen interface and the time pressure genuinely helps a child show their real ability rather than losing marks to surprise. The sensible approach is light familiarisation — enough that the format holds no shocks — combined with the broad reasoning practice that comes from regular verbal and non-verbal reasoning work, rather than the heavy drilling appropriate to a content-based grammar paper.
Common Pre-Test versus Common Entrance: what's the difference?
The two are easy to confuse and serve different stages. The Common Pre-Test is an early, online screening assessment — often in Year 6 — that schools use to decide whom to make a conditional offer to or invite to interview. Common Entrance is a later set of written exams, traditionally sat at 13+ (and sometimes 11+), usually after a conditional place has already been offered, to confirm a child is working at the expected standard before they join. In other words, the pre-test typically opens the door and Common Entrance later confirms it. Many families pursuing independent schools encounter the pre-test first and Common Entrance, if at all, much later. Our dedicated guide on the 11+ versus Common Entrance covers the full picture, including how this differs from the single-test grammar route. The practical implication for Year 5 and early Year 6 preparation is that the pre-test — and the four-subject reasoning and attainment base it rests on — is what most independent-school families should focus on first.
How to prepare for an independent school pre-test
The good news is that the foundations overlap almost entirely with grammar 11+ preparation. The four pre-test sections — English, Maths, Verbal Reasoning and Non-Verbal Reasoning — are the same four subjects a GL grammar paper tests, so the maths topic work, comprehension and vocabulary building, and reasoning practice you would do for a grammar target all count. Build comprehension and vocabulary through wide reading, using our reading list and vocabulary guide; work systematically through the maths topics; and build question-type fluency in the reasoning papers. The independent-specific additions are three: familiarity with the on-screen, adaptive format (so the interface is not a surprise); interview preparation, where genuine curiosity and the ability to talk about books and interests matter more than rehearsed answers; and, at some schools, a stronger emphasis on extended writing. Crucially, resist over-drilling: adaptive and cognitive tests reward genuine reasoning, and an exhausted, over-coached child tends to present worse at interview, not better.
Should I prepare differently for grammar and independent targets?
If your child is aiming at both a grammar school and one or more independent schools — a common and sensible hedge — you do not need two separate preparation programmes. The shared core is large: reading, vocabulary, maths fluency and reasoning practice serve every route. Build that core first. Then add the relatively small independent-specific layer: practice with the online format, some interview conversation, and any extra writing a particular school asks for. The main planning task is calendar management rather than content: independent assessments and grammar tests often fall in overlapping windows in the autumn of Year 6, so map every date — registration deadlines, test days and interviews — onto one calendar early, as our registration and deadlines guide describes. A single, well-built reasoning-and-attainment foundation is the most efficient way to keep several doors open at once.
How GrammarPrep supports independent-school families
GrammarPrep's four-subject adaptive practice — English, Maths, Verbal Reasoning and Non-Verbal Reasoning — maps directly onto the four sections of the ISEB Common Pre-Test, which makes it a natural fit for families preparing for independent as well as grammar targets. Because the practice is delivered on-screen and the FocusPlan adaptive engine adjusts difficulty in real time, children also get comfortable with the kind of adaptive, computer-based experience the pre-test itself uses. The free 15-minute diagnostic at grammarprep.uk/onboarding gives an honest picture of where your child stands across the four areas in a single sitting — no account required — which is a useful starting point whether you are aiming at a state grammar, an independent senior school, or both. For the broader strategic decision between the two routes, our independent versus grammar guide is the place to start.