Tests and scores

Updated 29 October 2026

GL Assessment scores explained

CAT4, the GL Progress Tests and the New Group Reading Test all report results the same way. This guide explains each number on the report, in plain English.

Which reports use these scores

GL Assessment's main school tests all use the same scale: a Standard Age Score with an average of 100 and a standard deviation of 15, plus a stanine and a percentile rank. That includes:

• CAT4, the reasoning test.
• The GL Progress Tests in maths, English and science.
• The New Group Reading Test (NGRT), which also gives a reading age.

Standard Age Score (SAS)

The SAS is the main number on every GL report (for NGRT, GL calls it "the most important piece of information"). It starts from your child's raw mark, adjusts it for their age in years and months, and places it on a scale that compares them with a nationally representative sample of UK children of the same age. So a child born in August is compared with other children born around the same time, not with classmates nearly a year older.

100 is average. Because the scale has a standard deviation of 15, about 68% of children score between 85 and 115. A score of 115 or 85 is therefore not unusual, while 130 or 70 is.

GL says the SAS is the fairest way to compare children across a year group or across years, and the best number for tracking progress.

Stanines

A stanine (short for "standard nine") groups the scores into nine bands. GL notes they are particularly useful when reporting to parents and students because they are easy to understand. GL's bands:

Stanines are deliberately broad. A score of 111 and a score of 104 are both stanine 6, while 111 and 112 sit in different stanines. So use the stanine for the big picture and the SAS for the detail.

Some reports use stanines for parts of a test. NGRT, for example, gives stanines for sentence completion and passage comprehension, and PTE gives stanines for English skills and for reading. GL's rough guide for NGRT is that a gap of two or more stanines between parts may show a real difference worth looking into.

National Percentile Rank (NPR)

The NPR is the percentage of children of the same age in the national sample who scored the same or lower. An NPR of 50 is average. GL's examples: an NPR of 5 means the score is within the lowest 5% of the sample, and 95 means it is within the highest 5%.

Percentiles stretch out in the middle and squeeze together at the ends. Moving from 100 to 105 lifts the percentile from about 50 to 63; moving from 130 to 135 only lifts it from about 98 to 99.

Score lookup

Percentiles are worked out from the SAS scale (average 100, standard deviation 15). The NPR printed on your child's report comes from GL's own tables for that test and can differ by a point or two. For every CAT4 score from 69 to 141, see CAT4 scores explained.

Other numbers you may see

Group rank

Your child's position within the group the school tested, such as the class or year group. An equals sign means a shared rank. It says nothing about the national picture.

Progress category

On the Progress Tests, if your child has taken the test before, the report compares the two results and gives one of five categories: much higher than expected, higher than expected, expected, lower than expected or much lower than expected. NGRT's progress report flags higher and lower than expected progress in a similar way. "Expected" means progress in line with what the earlier score would predict, which is a perfectly good result.

Reading age

NGRT also gives a reading age: the age at which a score is most likely to be achieved. GL warns it is not sensible to use reading ages for above-average readers and recommends the SAS for tracking progress. See NGRT scores and reading age.

Indicators

Teacher reports for CAT4, and for the Progress Tests, can include indicators of likely results in later UK exams. See CAT4 GCSE indicators and predicted grades.

Every score has a margin of error

No test measures perfectly. GL's technical documents give a 90% confidence band for each test: for an average child, there is a 90% chance the "true" score lies within this many points of the reported score.

GL also says that differences of less than 3 points are not usually statistically significant. So a child who scores 112 one year and 109 the next has, in practice, held steady.

Scores for children at schools in the UAE

GL uses its UK standardisation for international schools, so 100 always means the average for a UK child of the same age. GL has compared international schools with that average:

• CAT4: in GL's study of about 224,000 international students, the average was about 102 overall, slightly higher in quantitative, non-verbal and spatial reasoning but lower (about 97) in verbal reasoning. GL links this to the number of children learning English as an additional language.
• Progress Tests: international schools scored above 100 at every level in GL's 2023 benchmark, most of all in science.

The practical point: a score of 100 is exactly average nationally, but it may be below the middle of your child's class. Compare your child with their own earlier scores first.