Quick data guide
What data is available?
For each battery of CAT4 tests, the following information is available for each student:
- The number of questions attempted.
- A raw score, indicating how many questions were answered correctly.
Raw scores are interpreted by comparing them to the performance of other students using ‘normative scores’. Three types of normative scores are provided for the interpretation of performance:
- Standard Age Scores (SAS);
- National Percentile Rank (NPR) by age;
- Stanines (ST) by age.
Standard Age Score (SAS)
The Standard Age Score (SAS) is the most important piece of information derived from CAT4. The SAS is based on the student’s raw score which has been adjusted for age and placed on a scale that makes a comparison with a nationally representative sample of students of the same age across the UK. The average score is 100. The SAS is key to benchmarking and tracking progress and is the fairest way to compare the performance of different students within a year group or across year groups.
The SAS for each of the four batteries are given separately in the Individual Report and are averaged to give the mean score.
Schools that are based outside of the UK use SAS that are based on UK standardisation.
National Percentile Rank (NPR)
The National Percentile Rank (NPR) relates to the SAS and indicates the proportion of students of the same age who have scored the same as or below the student in question. For example, a student who achieves a percentile rank of 84 has scored equal to or better than 84% of students in the same age band.
An NPR of 5 means that the student’s score is within the lowest 5% of the national sample; an NPR of 95 means that the student’s score is within the highest 5% of the national sample; an NPR of 50 is average.
The stanine (ST or standard nine) places the student’s score on a scale of 1 (low) to 9 (high) and offers a broad overview of their performance.
This is a standardised score scale divided into nine bands. In a stanine scale the scores are grouped as shown in the table below. Stanines are particularly useful when reporting test results to students and parents as they are relatively easy to understand and interpret. They also avoid the erroneous impression of being ‘IQ scores’, sometimes attributed to SAS.
|The stanine scale|
|Stanine||Percentage of cases||Corresponding percentiles||Corresponding SAS|
|Very high||9||4%||97 and above||127 and above|
|Very low||1||4%||4 and below||73 and below|
For further information on these normative scores please see the ‘What test results can I obtain?’ and ‘Guidance on scoring and reporting results’ sections of the Teacher Guidance.