Is GCSE Computer Science Really Too Hard?

It's a common belief that GCSE Computer Science is too hard - but is it really?

Over the summer, a report was published that many interpreted as saying that GCSE Computer Science was too hard, but is that really what it said?

I also teach some GCSE Maths classes and, in that subject, exam questions can sometimes trend on social media, or even make the news, because they are so difficult that even Maths teachers struggle to answer them them. A recent example from an Edexcel Higher-tier paper is shown below.

Even some of the Foundation paper questions can require a reasonable degree of problem-solving ability, e.g.

On the other hand, I'm not sure that there has ever been GCSE Computer Science question that has been genuinely difficult. The questions that we tend to complain about are the ones where it's not clear if the knowledge required to answer them is explicitly mentioned in the specification (e.g. last year's question on the difference between sorting algorithms).

Some students do struggle with the programming questions, but I think that's generally down to insufficient practice. It can be difficult for them to come up with an algorithm under time pressure - we all know that it's better not to rush to coding - but questions on the programming papers are often very simple and generally quite samey, e.g. looping through an array.

There really aren't that many concepts in GCSE Computer Science as a whole, and lots of the topics depend on the same ideas, so it would be difficult to ask a student a question about which they know nothing.

In fact, when I was marking our mock exams last year, the thing that struck me is how easy it was to get a middling grade with very little specialist knowledge. Students giving vague answers with a level of detail barely beyond general knowledge were often getting a grade 4 or even 5.

However, I've also had students with excellent subject knowledge, and who are programming at a level that's beyond GCSE, using OOP and recursion, for example, who don't get a 9. The reason for this, I suspect, is the degree of pedantry in the mark scheme for questions that simply rely on declarative knowledge, e.g. the difference between a switch and a router.

So while I think that the GCSE Computer Science content isn't difficult, I have some sympathy with the idea that it's difficult to get a high grade. I think that's what the report is talking about, and it's not necessarily the same as the subject being too hard.

Convsersely, my impression of the grading of current A level exams is that too many students get high grades. Until 1987 exams were graded using statistical methods and grades were normally distributed, but this is the distribution of grades for Maths in 2024:

It's less common to see GCSE grades presented in this way, so I found the grade distributions for 2024 and plotted those. I chose Maths because it seemed to be a similar subject to Computer Science and French as it seemed to be different.

It looks like there were more more 6s, 8s and 9s in Computer Science than in both the other two subjects, and fewer 4s and 3 than either - also fewer 1s and 2s than Maths. Computer Science, therefore, doesn't seem to be the "hardest" subject by that measure either.

Finally... my daughter took her GCSEs in 2022, including Computer Science, so I asked her how it compared with other subjects. Her verdict? One of the easier subjects (and I wasn't allowed to help her with it because I "get all excited", apparently!).

This blog was originally written in September 2024.