What do progress 8 scores tell us about a school's performance?

What is a progress 8 score?

The Progress 8 score is considered by many to be an important metric when comparing the academic performance of different schools. Alongside the Attainment 8 score, it was introduced by Michael Gove in 2016 to reform how the performances of individual students were judged and how schools as a whole could be compared. The idea of new the system was to widen the lens and, rather than looking at how many C grades and above were achieved in English or maths, to switch the focus and look instead at how well all pupils had performed across a much broader range of subjects.

To fully understand the Progress 8 score it’s worth first getting familiar with what an Attainment 8 score is. You can read our summary here. However, put simply, while Attainment 8 takes the average grades for all pupils across 8 GCSE subjects and returns a score, Progress 8 goes one step further and compares this score against those of pupils who performed similarly at Key Stage 2 (SATs). By looking at how well each pupil has fared relative to those of roughly the same ability, we can analyse deviations from the average score and assess to what extent individual schools may be responsible for any differences noted.

How is it calculated?

Pupils are first grouped together according to their ‘prior attainment’ (i.e. their grades at Key Stage 2). Their individual Attainment 8 score is then compared with that of the average across their prior attainment group. Any difference between their score and the average is divided by 10 to give the pupil their Progress 8 score. As you would expect, a school’s Progress 8 score is simply the average of all of its students for that particular year.

For example, Fred’s Attainment 8 score is 58 and the national average of all pupils who performed similarly to him at Key Stage 2 is 56. Therefore Fred’s score is +2 relative to the average for his prior attainment group. Dividing this number by 10 we get Fred’s Progress 8 score of 0.2.

John is in the same prior attainment group as Fred but achieved an Attainment 8 score of 55. John’s progress score is therefore -0.1 since it is one point less than the average for the group.

What does it tell us?

The majority of schools will receive a Progress 8 score on or around zero, meaning that most pupils there did roughly as well at GCSE-level as they did at Key Stage 2. Scores above zero mean that pupils did, on average, better than they did at key Stage 2 – with negative scores indicating they mostly did worse.

While there is a lower data confidence for smaller schools where the average is more easily skewed by a couple of exceptionally high or low scores, Progress 8 can certainly be a useful indicator of whether the school itself is the decisive factor in whether pupils perform above or below their expected trajectory.