Progress 8 is a secondary accountability measure introduced in 2016, designed to assess pupils' progress across eight subjects by comparing their results to peers with similar prior attainment. It is linked to another measure, Attainment 8, which calculates a student's average grade in these subjects, and both scores will be published in performance tables. Schools with a Progress 8 score below -0.5 will trigger an Ofsted inspection, as it indicates below-average pupil performance.