Hi, depends on the subject. I mark chemistry, and there is not much leeway at all. We normally accept synonyms unless there is a special term you have to mention (usually it’s written in bold in the mark schemes, so definitely pay attention to those words). For some explanatory questions the mark schemes are very strict, and I very often see the answers which I’d give a mark for, but the mark scheme won’t allow it. And sometimes the answer accepted in one board would get a zero in another. On the other hand, ECFs for calculations are usually very straightforward, so at least that works well in A-levels. The most difficult questions to mark are 6 markers (the ones with a communication mark and levels of answer) - these are often very subjective, and it’s common to have a difference of 1-2 marks between me and the moderator who checks my marking.