I'm often reliably informed that art is an easier exam option, usually by people who have little or no direct experience of teaching art. Well I've taught Art, DT, Maths, Media Studies, ICT and English to exam level and I can tell you that this is nonsense. This misconception of 'easiness' comes from the fact that art gets higher grades on average than many other subjects, but this does not necessarily equate to it being easier. If anything it is equally difficult if not more so.
In art, evidence of attainment is a visible and tangible product produced over a two year period. Once met this evidence is standardised and fixed. What's more, grades accumulate
over the extent course. This method gives teachers time to guide their students over a longer time period but it also means that most coursework is valuable evidence for final portfolio. Fail a piece of coursework or miss anything and you could be in trouble and it can take a superhuman effort to pull it back. (This is common and often happens toward the end of year 11). Also, since art is very skills led and content rich it is very demanding on input time and application for student. In other words, it takes a long time to do and a lot of effort.
The other common misconception is that art is easier because students self select it which must mean they are good at it and they like it. This has some truth to it but it's also quite a warped perspective because ability in exam art is seldom related to the pupil's perception of the kind of art they like doing. It's a lot like being good with times tables and being expected to be good at complex algebra. The two are related, yet quite different disciplines. Also, many high attaining students are steered into academic subjects and prevented from taking art. Add to this the common SLT practice of nudging less able pupils into 'soft option' art subjects and you rarely have a cohort who love art and are good at it. What you invariably get are lots of middle ability students who need a LOT of teacher guidance.
Good art grades come from enormous teacher effort and expertise with well planned art projects that provide good structure, drive motivation, extend the highly able and support the less able. These projects aren't in a text book or given out to art teachers, they have to individually written to suit the needs of their students. Few other subjects have the pressure of having to write the course content as well as delivering it.
In most other subjects attainment is purely exam led and as such grades are more precarious and reliant on performance in one or two tests rather than the whole course. This doesn't make them harder subjects, it means the testing procedure is less dependable. For example, my teachers at school were flabbergasted when I failed Physics because I was one of the top students in class. But on the day of the exam I froze and messed up.
This doesn't often happen in art because our assessment procedure lasts two years not two hours.
This assessment over time is why we get better exam results not because art is easier to do or because we have classes full of eager, talented students.