"Prior attainment" refers to an individual's achievements or educational level before a specific point in time. It is a measure of what someone has already accomplished or learned in the past. Full definition
As more pupils with lower prior attainment took the subjects it was expected the proportion of passes would decrease — and it did. (schoolsweek.co.uk)
In every classroom there are children with different levels of prior attainment who have differing capacities to engage with the work. (schoolsweek.co.uk)
According to an annual report, out of 48 academy chains, only eight saw poorer pupils with high prior attainment go on to progress over the national average. (educationbusinessuk.net)