KS4 comprises Years 10 and 11, when students are working towards GCSEs. Some subjects are
compulsory; these are known as the core and foundation subjects. It’s up to schools to decide
how many hours of teaching they allocate to each subject, but the core subjects typically have
more teaching time. This is because they are ‘double-weighted’ in league tables to reflect their
importance (in other words, each GCSE result in English, maths and science is worth two GCSEs
in other subjects), so it’s in schools’ interest to make sure students get good results in these
subjects.