11+ Standardised Scores vs IQ: Why a 121 Is Not an IQ of 121

The 2026 11+ season is under way. Buckinghamshire's Secondary Transfer Test was sat on 10 September and results go out by email after 4pm on 9 October, and Medway's results are due on 14 October. Every year the same question follows. A parent sees "standardised score 121" on a results page, recognises 121 as a very high IQ, and assumes the child has scored one. It has not. The two numbers sit on similar-looking scales, but they are built differently, and the councils' own figures show it.

What an 11+ standardised score is

A raw score is the number of questions answered correctly. A standardised score converts it into a position relative to other children, adjusted for age, so that a child who sat the test just after their birthday and one who sat it just before the next are compared fairly. Buckinghamshire says its process takes account of each child's age in years and months on the test date, and Medway says it standardises for age so that children born later in the school year are not disadvantaged. The adjustment matters because the youngest children in a year group score lower on average, an effect covered in our piece on the relative age effect.

GL Assessment, which marks the Buckinghamshire papers, describes standard scores in its published guidance as having a mean of 100 and a standard deviation (SD, the typical spread of scores) of 15. That is the same convention IQ tests use, which is why a 121 looks like an IQ. But the guidance we read covers GL's assessments in general, and neither council page we read states the mean or the SD of the transfer-test scale.

The Buckinghamshire numbers do not fit an IQ scale

Buckinghamshire's marking page says a child qualifies with a Secondary Transfer Test score (STTS) of 121 or above, that the score runs between 60 and 170, and that the council expects about 37% of children to reach 121. The results page words the 121 line more carefully: children on 121 or more are eligible to be considered for a grammar school place, not guaranteed one. Now put the same numbers on an IQ-style curve, with a mean of 100 and an SD of 15. A 121 sits 1.4 SD above the mean, at the 91.9th percentile, which leaves only 8.1% of people above it. For 37% to sit above the cut, the cut would have to be near 105.

• Read as an IQ-style score (mean 100, SD 15): 121 is the 91.9th percentile, the top 8.1%
• Buckinghamshire's own expectation: about 37% of children reach 121
• The same 37% on an IQ-style curve: the cut would sit near 105

So the 121 is not a position on a mean-100, SD-15 curve over the children who sat the test. The pages we read do not publish the mean and SD behind Buckinghamshire's 60-to-170 scale, so we cannot say how it was built. We can say what reading it as an IQ does: a 121 sounds about 4.6 times rarer than the council expects it to be, since 8.1% against 37% is a factor of 4.6. Our percentile calculator shows the IQ-style figure for any score you type in.

Medway sets its mark by rank, not by a fixed score

Medway does it another way. Its page describes a weighted total: the English standardised score times two, plus the mathematics standardised score times two, plus the reasoning standardised score times one. All children from Medway maintained schools are then ordered by that total, and the highest-scoring 26% are assessed as grammar. The pass mark is therefore whatever total falls on that 26% line. It cannot be known before the results are in, and it means nothing outside that year and that area. Buckinghamshire weights its sections differently: 50% verbal, 25% mathematical and 25% non-verbal.

Both cuts, redrawn on an IQ-style curve

A quick way to compare the two areas is to ask where each cut would sit if a cohort's scores followed a mean-100, SD-15 curve. That is a thought experiment, not how either council calculates anything, but it shows how far the headline numbers sit from an IQ. Buckinghamshire's 37% would put the cut near 105, and Medway's 26% would put it near 110 (109.65, to be exact). Both are a long way below 121, and neither is anywhere near the IQ of 130 that our guide to how rare a high IQ score is shows to be the top 2.3% of a national sample.

• Buckinghamshire: about 37% reach the cut, which is near 105 on an IQ-style curve
• Medway: the top 26% are assessed as grammar, which is near 110 on an IQ-style curve
• An IQ of 121 (mean 100, SD 15): the top 8.1% of a national norm sample

Fixed score or fixed share?

The two systems answer different questions. A fixed score, as in Buckinghamshire, tells a family the number to aim for, but the share who reach it is an expectation, not a quota: the council says it expects about 37%, and says standardisation balances the overall performance of children from one year to the next. A fixed share, as in Medway, guarantees that roughly the same proportion qualify every year, but the score that marks the line is only known once the results are in. Neither is a measure of IQ, and neither tells you whether a child would clear the other area's bar.

What the 11+ measures, and what IQ tests measure

Both councils' formulas mix school-taught content with reasoning. Medway's covers English, mathematics and reasoning, and Buckinghamshire's covers verbal, mathematical and non-verbal skills. Those are group-administered papers, closer to the achievement tests our article on achievement versus IQ tests describes than to an individually administered IQ battery such as the one behind WISC-V index scores. Neither council page mentions IQ. Non-verbal reasoning items generally use shapes and patterns rather than words, the same family of item as on our culture-fair test, and our explainer on CogAT and NNAT scores shows the same age-standardised logic in a US school-entry test.

What a score cannot tell you

A standardised score ranks a child against a cohort on one day. It does not say how high the child's IQ is, how they would score on a different test, or how much of the result is preparation. A 2013 press release from UCL's Institute of Education reported that seven in ten children who had gained a grammar school place had received private tutoring. That came from a survey of 212 pupils at two grammar schools, so it says little about the whole country, but it is a reminder of why our piece on what practice actually changes on a test matters here.

How to use the number

Three habits keep the number useful. First, check your own council's page for the pass rule and for how it standardises, because the rules differ by area: a fixed score in Buckinghamshire, a rank line in Medway. Second, never convert a pass mark into an IQ. The percentile calculator is for scores that really sit on a mean-100, SD-15 scale, and the IQ bell curve shows what those percentiles mean. Third, treat any IQ-style figure for a child as a separate measurement from a different test. The IQ Metrics kids test for ages 8 to 12 reports a score against age norms, but it is not the 11+ and it does not predict a pass mark.

The short version: an 11+ standardised score answers "how did this child rank among these children, adjusted for age?" An IQ score answers "how does this person compare with a national norm sample?" Both sit on a scale centred on 100, which is where the confusion starts. Our guide to gifted cut-off scores and the IQ Metrics test use the second meaning.

Common questions