It is a system of how the government measures how successful a school is with the progress of their students.
This scale looks at where students were academically in year 7 and how they have progressed to their expected grades to the end of year 11.
It is measured with buckets: one is English which gets two, another is Maths which also gets two, then there is; History, Geography, Science, Computer Science, and a Language in one bucket, and the last bucket is any other subjects that a student takes but it has to be 3 subjects.
The top of the scale is +1 and the bottom is -1 but 0 is good