Understanding your data

The Group Report for Teachers provides an easy to understand overview of reading attainment in a selected group or cohort. Your Standard Age Score (SAS) and reading age data will help you to understand starting points, helping you plan your curriculum. Group rank will help you quickly and easily identify those most in need of additional support and is best accessed in Excel Report. 

The Individual Report for Teachers offers analysis of the test section answers achieved by each student. 

Standard Age Score (SAS)

This is the most important piece of information derived from NGRT. The SAS is based on the number of questions a student has answered correctly; the score is 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 Standard Age Score indicates the degree to which an individual’s score deviates from the average of pupils of the same age. The scale is based on the ‘normal’ distribution of scores that would be expected within the population and is calculated on the basis that the overall mean (average) standard age score is 100 and the standard deviation is 15, so that about 68% of people will score between 85 and 115.

Overall Stanine

This places the student’s score on a scale of 1 (low) to 9 (high) and offers a broad overview of their performance.

Reading age

This is the age at which a score is most likely to be achieved based on the national sample.

National Percentile Rank (NPR)

This related to the SAS and indicated the percentage of students obtaining any score. NPR of 50 is average. NPR of 5 means that the student’s score is within the lowest 5% of the national sample; NPR of 95 means that the student’s score is within the highest 5% of the national sample.

Reading Ability Scale

This is a development scale and can be used to monitor a student’s reading ability or development over time. The values on the scale are 0 to 600 – a higher scale score represents a higher reading ability level. The reading ability of a student aged 6 years is around 200; for age 9 years it is around 300; and for age 16 it is around 400.

NGRT digital only data

For NGRT digital, all students start with Sentence Completion, which provides insight into vocabulary gaps. Depending on performance, students will then continue onto either the Passage Comprehension or Phonics sections. 

For students who complete the Passage Comprehension section, the Sentence Completion and Passage Comprehension stanines will help you to understand your students’ strengths and weaknesses. Stanines are closely linked to SAS and place students’ scores on a scale of 1 (low) to 9 (high) offering a broad overview of performance. Discrepancies of 2 or more stanines are highlighted in the Group Report for Teachers, as these students would benefit from further investigation – please see our reading diagnostic pathway for more information. You can also explore an analysis of Passage Comprehension responses by question type best accessed through the Individual Student Report for Teachers, which will help pinpoint where difficulties lie. 

For students who completed the Phonics section, you may wish to consider students’ scores to help identify next steps, best accessed through the Individual Student Report for Teachers. 

When completed termly, the NGRT Progress Report provides a summary of the progress made over time. Progress categories highlight those who have made higher or lower than expected progress in comparison to previous test scores, making it even quicker and easier to identify successes and those in need of further support or intervention. Please note – it is always best to use SAS for measuring progress or monitoring trends. 

Reading Ability Scale

With an adaptive test, students within a class answer different questions depending on their abilities. Weaker students attempt easier questions whereas more able students attempt harder questions. Therefore a weaker or a more able student may get the same number of questions correct but they will have different abilities. The ability scale score takes into account the difficulty of the questions a student has attempted and is the adaptive equivalent to the raw score for a static test. Any use of raw scores in a fixed test applies to the ability scale. The advantage with the NGRT scale score is that you can use it to track the absolute Reading ability of an individual over time. SAS scores are adjusted for age and the average SAS score at any age group nationally is 100.

The chart and table below shows the percentile distribution of the scale score by age. It shows that the average (50th percentile) scale score for students at age 7 is 228 and increases to 342 at age 12. The top 10% of students (i.e. 90th percentile) at age 7 have a scale score of 308 or higher and at age 12 the top 10% of students have a scale score of 400 or higher.

Reading Ages

Reading ages are not the same as Reading attainment. Reading ages are derived from the average raw or scale scores at different age points. The red line in the chart shows the average scale scores e.g. the average scale score for 8 year old students is 272. Therefore, any student with a scale score of 272 will have a Reading age of 8 years. For example, a 12 year old student with a scale score of 276 and in the bottom 10th percentile will have an age-equivalent close to 8 years (as shown in the black lines below).

The year on year average growth in Reading ability is much higher at younger ages (e.g. average increase from 228 to 272 between ages 7 and 8 years). For older students the year on year growth is much smaller over ages 13 years (e.g. average increase from 368 to 376 between ages 14 to 15 years). Therefore, a Reading age of 17 years is unlikely to be that much different from a Reading age of 14 years. In most cases it is not sensible to relate scores for students with above average ability to Reading age as Reading ages relate to an average. In this example, the most we can say about a 12 year old student with a scale score of 400 and in the top 10th percentile is that their Reading age is higher than 15 years (refer to the orange line). Therefore, there are issues with using Reading ages especially with above average students and it is best to use standard age scores (SAS) for measuring progress or monitor trends.


NGRT What Data is Provided?

NGRT What Does the Data Mean?

NGRT Implications for teaching and learning