So, Essex University requires that examination candidates indicate on the front of their answer booklet which questions they have answered. This is for three reasons:
1) So markers can tell if they've missed marking a question.
2) So markers have somewhere to put the mark totals per question (and the overall mark).
3) So that if different people are marking different questions, they can see who needs to mark which script.
Unfortunately, the university doesn't tell the candidates what constitutes a "question". This means we get lists of attempted questions in a variety of formats, not all of which are ideal for the marker.
All my exams this year had five questions and students had to answer them all. Here's a sample of some of the ways candidates recorded which questions they answered.
The final three shown suited my purposes, but I had to rewrite (or, in one case, write) the rest in red pen.
Not present are examples of ones which list the questions in the order attempted rather than in numerical order. Also omitted are the ones that miss questions out. I decided not to include them so that if past or present students recognised their handiwork they didn't gain an impression that I was laughing at them (I'm not) or that writing it "wrongly" cost them marks (it didn't).
What this exercise shows is that a simple instruction can yield multiple interpretations.
Examination questions themselves are basically sets of complicated instructions.
You perhaps can see why sometimes smart students don't pick up as many marks as their understanding of the subject matter perhaps merits.