CAT4 Scores Explained: SAS, Stanines and What a Good Score Is

CAT4 results come as a Standard Age Score, or SAS, for each of four batteries, on a scale where the average for every age group is 100 and the standard deviation is 15. On GL Assessment's own table, 89 to 111 is the average band and 127 or more is stanine 9, the top 4 per cent. CAT4 is not presented as an IQ test, but its scale looks like one, and this guide shows where the resemblance stops, what a good score is and what the highest possible score is.

What does CAT4 measure and who sits it?

The Cognitive Abilities Test, Fourth Edition, is published by GL Assessment. It has four batteries: verbal reasoning, which GL describes as thinking with words; quantitative reasoning, thinking with numbers; non-verbal reasoning, thinking with shape; and spatial reasoning, thinking with shape and space. GL's product page says it is for pupils aged 6 to 17 and over, with two 30-minute sessions for ages 6 to 8 and three 45-minute sessions from 8 upwards, online on a computer or tablet or on paper, at any point in the year.

There are nine levels, from X and Pre-A up to G, matched to age. Level D covers ages 10 years 6 months to 12 years 11 months, which is Year 7. GL recommends using CAT4 at the start of Year 7 to benchmark new students and again in Year 9 or Year 10, to set realistic targets and to spot those who are underperforming or need extra challenge.

What is a Standard Age Score?

GL's teacher guidance says the average for each age group is set to 100 and the standard deviation to 15. A standard deviation is the typical distance of a score from the average, so on this scale about two-thirds of pupils score between 85 and 115. A score compares a pupil with others in the same age band, not with the whole cohort, and GL also reports a national percentile rank: a pupil on the 84th percentile has scored equal to or better than 84 per cent of the same age band.

Our z-score guide shows the arithmetic, and the percentile calculator gives the same percentile for a SAS as for an IQ with the same mean and spread, so a SAS of 120 is about the 91st percentile.

What do CAT4 stanines mean?

Stanines cut the scale into nine bands, so a report shows one digit instead of a number with a false air of precision. GL's quick data guide gives the table below. Its bands are our reading of the merged cells in that table, and GL's admissions guide confirms that its average category runs from 89 to 111.

• Stanine 9: SAS 127 and above, top 4 per cent (percentile 97 and over), very high
• Stanine 8: SAS 119 to 126, 7 per cent (percentile 90 to 96), above average
• Stanine 7: SAS 112 to 118, 12 per cent (percentile 78 to 89), above average
• Stanine 6: SAS 104 to 111, 17 per cent (percentile 59 to 77), average
• Stanine 5: SAS 97 to 103, 20 per cent (percentile 41 to 58), average
• Stanine 4: SAS 89 to 96, 17 per cent (percentile 23 to 40), average
• Stanine 3: SAS 82 to 88, 12 per cent (percentile 12 to 22), below average
• Stanine 2: SAS 74 to 81, 7 per cent (percentile 5 to 11), below average
• Stanine 1: SAS 73 and below, 4 per cent (percentile 4 and below), very low

We checked the table against the bell curve. Cutting a normal curve with mean 100 and SD 15 at the stanine boundaries puts them at SAS 73.7, 81.6, 88.9, 96.2, 103.8, 111.1, 118.4 and 126.3, and GL's bands are those figures rounded to the next whole score. So the table is standard stanine arithmetic and holds no CAT4-specific surprise.

What is a good CAT4 score?

There is no single answer, because GL publishes bands and leaves the threshold for any decision to schools. On GL's bands, 89 to 111 is average, 112 to 126 is above average, and 127 or more is very high. GL's admissions guide says a sample pupil who is above average in all four batteries "should be considered" for a school's gifted and talented policy, but we found no GL cut-off for that.

Schools set their own. The Exceptional Learners policy of Cambridge International School Dubai, part of the GEMS group and reviewed in August 2024, treats a standardised score of 127 or above in any CAT4 battery as within the top 5 per cent of the general population, and asks for an overall score of 130 or more, with at least two batteries at 127 or above. GL's table puts 127 at the top 4 per cent, and on our arithmetic a SAS of 127 with SD 15 is the 96.4th percentile, the top 3.6 per cent. The same number on a scale with SD 16, such as the CogAT's, is the 95.4th percentile, the top 4.6 per cent, which is one reason a threshold should always be read with its scale. Our guide to CogAT and NNAT scores and to SD 15 against SD 16 covers the difference.

What is the highest CAT4 score?

GL's teacher guidance gives the limits of the SAS as 59 to 141 for levels Pre-A to G and 69 to 131 for levels X and Y, because the youngest levels are less reliable. A case study in the same guidance shows a pupil with an SAS of 141, stanine 9 and a percentile rank of 100. That makes 141 the highest score on a single battery. A footnote in the same document says that over 99 per cent scored between 60 and 140, so GL's own text differs by a point on the limits. Because an average of four batteries cannot exceed the highest of them, 141 is also the ceiling for a mean SAS.

Is CAT4 an IQ test?

GL does not describe it as one. Its guidance calls CAT4 a measure of ability, not attainment, and its quick data guide says stanines avoid the erroneous impression of being IQ scores, sometimes attributed to the SAS. We found no comparison of CAT4 with a Wechsler scale in GL's teacher guidance or its technical report, and the report never uses the word IQ.

What GL does publish is stability and prediction. In a study of 3,883 students who took Level D and then Level F two years later, the correlation of the mean SAS across the two occasions was 0.88. With a correlation of 0.88 and the same spread on both occasions, individual scores typically move by about 7 points either way over two years, roughly one stanine. GL also reports correlations of the mean CAT4 score with Key Stage 2 results of 0.70 for maths, 0.67 for reading and 0.66 for grammar, punctuation and spelling, so CAT4 tracks attainment closely without being the same thing. The technical report says the tests were standardised between September and December 2011 on 24,708 pupils in England, Wales, Scotland and Northern Ireland, weighted to correct for sample bias, with levels X and Y standardised in 2014. GL's product page adds that results are verified every year on a quarter of a million students. Our piece on the Flynn effect and expiring norms explains why the age of a norm sample matters.

What do schools do with a CAT4 profile?

Beyond the scores, GL reports a learning profile that compares the verbal and spatial batteries, with seven categories from extreme verbal bias through no bias to extreme spatial bias. Schools use the profile and the stanines to set targets and to decide who gets extra challenge or extra support. A stanine is a coarse measure, and our guide to IQ score margin of error shows why a single score should be read as a range. For the wider picture of how UK selective tests use the same style of standard score, see our guide to 11+ standardised scores and IQ.

What should parents do with a CAT4 report?

Ask the school which battery or batteries and which stanine or SAS threshold it uses for any decision, and which level and date the test was taken. Read the report as a profile, not a rank, and keep the age of the norms in mind. Do not convert a SAS to an IQ, since the two are on the same scale but were not normed on the same people. Practice on the same kinds of reasoning is possible with our verbal, numerical and spatial tests and our culture-fair test for non-verbal reasoning, and our IQ test for ages 8 to 12 is built for the same age band. Our guide to reading an IQ test report covers the rest.

A CAT4 standard age score is a statement about rank among pupils of the same age on 2011 norms, not a fixed trait and not an IQ. The IQ Metrics test reports its score on the IQ scale with the percentile beside it, and the bell curve page shows where each band sits. Another UK selection test, the UCAT, reports deciles among applicants rather than an IQ-style scale; see our guide to UCAT scores.

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