S-Scores FAQ

S-Scores FAQ

1) What do these numbers mean?

S-Scores are standardised scores that describe a pupil’s achievement in an assessment compared to the achievements of other students of the same age nationally.  The score is not a percentage or a percentile rank but a number which is intended to describe the level of skill or knowledge they have displayed in the assessment, like a very fine grade.

2) Why not just give us the percentage they scored; wouldn’t that make more sense?

When appropriate we will also include a percentage but there are some problems with percentage scores:

  1. Percentages only make sense if you know how hard the assessment was. From one assessment to the next the average and the spread of scores achieved by students could vary significantly and without this information it is hard to judge whether a student’s performance has been sustained, improved or decreased.
  2. Increasingly we are using comparative judgement approaches in our assessments which mean that there is no raw mark to calculate a percentage from: the output of the comparison process is a standardised score
  3. We sometimes use different tiers of examination paper within a year group. A student scoring 80% on a foundation paper might actually be achieving less than a student achieving 40% on a higher paper.  With S-Scores we can combine both scores onto the same scale.

3) What sort of range do these scores come in?

The s-scores are shown in the bottom line of the chart below (SAS). They range from about 60 to about 140 but the majority of scores lie between 85 and 115.

4) What about Percentile Ranking?

Percentile ranks are shown as “PR” in the chart above.  We don’t generally use Percentile Ranking because a small change of marks near the average produces a big change in a child’s Percentile Ranking without representing a significant change in their achievements.  This is simply because the majority of scores are close to average, so percentile ranking in this area is highly volatile and not very meaningful.

5) What does the Stanine represent?

Stanine stands for “standard nine” and is a way of reducing a standardised score to a single digit where 1 is the lowest range of achievement and 9 is the highest.  Although they are a feature of the GL Assessment results, we don’t generally use stanines when working with students because they are too easily confused with the new GCSE grades 1-9 which look similar but are not the same.

6) Should I be worried if my child’s score has decreased from previous assessments?

The s-score approach is intended to make it clear if a student’s performance has dropped, or risen.  However, scores in assessments will not always remain the same even when a student is working and learning as expected.  Parents/ carers and students need to consider the things before reaching a conclusion about whether there is a serious issue to confront:

  1. All assessment approaches have flaws. The process of measuring learning is not as simple as, for example, measuring our height or weight.  It is possible that a student has been learning well but perhaps lost a lot of marks in an assessment through misunderstanding what was being asked for.  Equally, even when a student has produced a performance which reflects their abilities well the process of marking that piece of work is also subject to human nature: teachers sometimes make mistakes or judge things differently to previous assessors.
  2. Remember that an assessment measures a child’s performance in a particular task undertaken on a particular day. We then try to draw a conclusion about what the child’s underlying level of ability is in a particular subject at that time.  This conclusion is not always valid because the task that was set will not always give the pupil an opportunity to demonstrate the full range of their knowledge or abilities in that subject.  Equally children, like adults have off-days: they may simply not have been feeling on good form on the day of the exam.
  3. Be aware that although S-Scores look very precise, even very high quality assessment of relatively easy to measure abilities is, at best, accurate to about +/- 5 points on this scale
  4. Consider the other evidence: has the child been working hard on their homework in that subject? Did they prepare sensibly for the assessment?  Is the child spending a sensible amount of time reading and writing on a daily basis, or are evenings often spent watching videos or playing games?  A child who has been working hard and focusing on the right things can be learning effectively but have a bad day in an exam: piling parental anxiety on to them is unlikely to help their performance in the long term.  On the other hand a child who is not adopting the right approach to studying may well need a clear indication through a low s-score that their approach is not good enough for them to succeed in their learning.

7) What sort of score should I expect my child to achieve?

Put simply: you should expect them to maintain their standardised score, or improve it.  However, variation in scores is normal: if a child has scored within 10 points of the relevant baseline it is likely that they are performing about as well as we should expect.

That does not mean that students should not be ambitious and aiming to beat their prior Personal Best.

8) What do you mean by the “relevant baseline”?

We benchmark students’ achievements on entry so that we know what we can reasonably expect of them during their time at school.  Because we never wish to limit a child’s view of their academic potential this baseline is regarded only as a starting point in our Personal Bests approach.  Every time a child proves that they can beat their prior Personal Best we revise our expectations of them.  However, it is still often helpful to refer back to the baseline of their achievement on entry.

When students arrive at school in Year 7 we set them a range of assessments:

  • GL Assessment Cognitive Abilities Test: Fourth Edition (CAT4). This provides a standardised measure of cognitive reasoning ability, without reference to curriculum-based material and regardless of previous achievements or first language.  Whilst no assessment can measure innate ability or “intelligence” this one is as independent as possible of the material their prior education may have focused on.

This assessment produces standardised scores for:

  • Verbal reasoning
  • Non-verbal reasoning
  • Quantitative athematical reasoning
  • Spatial reasoning
  • From 2016 we have also set Year 7 students the GL Assessment Transition Tests in English, mathematics and science. These produce standardised scores in the following three areas of knowledge and reasoning
    • The Progress Test in English (PTE) is a standardised assessment of a pupil’s technical English skills (spelling, grammar and punctuation) and reading comprehension. It should be noted that this does not assess their ability to analyse texts, or their creative or factual writing abilities. Some students have a very different level of skill in technical English compared to their writing ability or the power of their imagination.
    • The Progress Test in Mathematics (PTM) is a standardised assessment of pupils’ mathematical skills and knowledge which assesses two dimensions of maths learning: mathematical content knowledge and the understanding and application of mathematical processes through reasoning and problem solving.
    • The Progress Test in Science (PTS) is a standardised assessment of a pupil’s science achievement against their peers nationally, which measures their scientific knowledge as well as their ability to ‘work scientifically’.

We also consider the child’s performance in the Key Stage 2 assessments (Year 6 “SATs”) and convert this to a Year 7 baseline standardised score so that it is on the same scale as the GL Assessment results and the examinations that they will be set in school.  The combination of Key Stage 2 assessments with GL Assessment’s CAT4 and transition tests gives us a measure of students’ performance on arrival at the high school.  This gives us a firm foundation from which to measure their progress over time.

So which scores contribute to the baselines for the different subjects?

SubjectBenchmarks consideredComments
English reading

Key Stage 2 English (Reading) assessment

CAT4 Verbal

GL PTE Transition Test (for students starting Year 7 from 2016 onwards)

English writing

Key Stage 2 English (Reading) assessment

CAT4 Verbal

GL PTE Transition Test (for students starting Year 7 from 2016 onwards)

Proceed with caution!  Writing ability is very difficult to measure reliably and none of the benchmarks we have are particularly reliable indicators.  Key Stage 2 assessments do not attempt to measure writing ability in the same way the GCSE English Language does.

Key Stage 2 Mathematics

CAT4 Mathematical

GL PTM Transition Test (for students starting Year 7 from 2016 onwards)

Other subjects

Key Stage 2 English (Reading) assessment and Mathematics assessment.

CAT 4  Verbal, non-verbal, quantitative and spatial

GL PTE, PTM and PTS Transition Test (for students starting Year 7 from 2016 onwards)