Students generally study for A levels over a two-year period. For much of their history, A levels have been examined by "terminal" examinations taken at the end of these two years. A more modular approach to examination became common in many subjects starting in the late 1980s, and standard for September 2000 and later cohorts, with students taking their subjects to the half-credit "AS" level after one year and proceeding to full A level the next year (sometimes in fewer subjects). In 2015, Ofqual decided to change back to a terminal approach where students sit all examinations at the end of the second year. AS is still offered, but as a separate qualification; AS grades no longer count towards a subsequent A level.
