Less Is More

How many different topics are there in the National Curriculum for Computing? Do you possibly think that there's more to Computing than there actually is?

Teaching is ultimately about getting the students to remember things. The better they remember, the more they will understand and the more likely they are to become "good" at your subject.

Some things just seem intuitive - if there are fewer "things" to remember, then "success" should be easier, so when I saw a page of CfEM Mastery Principles, item 3 made perfect sense. It's aimed at Maths teachers, but it strikes me that it would be applicable in most subjects, so in my role as lead teacher I made it a shared target for the team.

Curriculum Coherence

The idea is that if you can link together techniques that use the same concept then you're effectively reducing the number of "things" that the student needs to remember.

It's something that I've always done in Maths. You can make sure that students are confident with fractions, then point out that pie charts are fractions of circles, that probability is just the fraction of the time that things happen, and so on.

The curriculum map on the Computing Resources page shows how the topics that you might include in a Computing curriculum could be linked. Many of these things, however, actually overlap.

Recently, in the space of a week, I found myself explaining the same concept in three different contexts. It inspired me to make the range of binary values page. When discussing representation, for example, the number of colours that can be represented in n bits is 2n. That's also the number of discrete values that a sound sample can take, and the number of memory locations that can be addressed with an n-bit MAR (or data bus) and the number of rows of inputs required in the truth table for a logic circuit with n inputs.

This idea of combinations also extends into networking (e.g. why we needed to change from IPv4 to IPv6), compression and security (e.g. password strength and brute force attacks) and, if we think about a broader range of things with two states, that takes us into storage technologies (i.e. whether things reflect or are charged, or the direction of the magnetic field), transmission of data (serial, parallel, parity, etc.), logic circuits and how the ALU works.

Add in representation and we can talk about character sets, images and sound, what compilers and interpreters do, the contents of network packets (and what firewalls do) and truth values and Boolean logic.

So just those two ideas - things having two states and representing things as numbers - cover pretty-much the whole of the GCSE theory content.

As subject specialists with a view of the whole scheme of work we can identify opportunities to make these links within our subject and it's something that I do all the time. Practically every lesson gives me an opportunity to remind students of something else. I suspect that's why educational researchers such as John Hattie believe that buying a scheme of work (or just using someone else's) can be detrimental to student progress; if we're following individual lessons and not thinking about the course as a whole then we can miss those links.

Last December I attended the NCCE Big Computing Leadership Conference in Oxford. I find that it's quite common to discover fascinating things by accident at such events. At a CAS conference in Birmingham a few years ago, I went to a talk about cyber-crime by the police - essentially because there was nothing else on at the same time that I fancied - and it turned out to be the most interesting talk of the day. In Oxford, I went to a session with Tig Williams on the Computing curriculum, even though I thought my curriculum was pretty-well sorted (probably because some sessions at conferences are less applicable to someone who doesn't work in a school).

Well... as it says in all the best clickbait headlines, my mind was blown! Tig showed the nine bullet points from the KS3 Computing curriculum and asked how many topics or units we thought were there. Now I don't really teach in "units", but I have rough groupings of ideas - a similar idea to the "strands" we used to have in the old National Curriculum.

When Computing was first introduced in 2014, not counting e-safety (which I've never thought fitted in Computing), I thought that there were maybe five areas for KS3 and GCSE:

My current thinking is that it's maybe four, because a lot of networking is a mixture of mathematics (i.e. graph theory - how nodes are connected) and representation (i.e. the content of what you're sending and the addressing mechanism). Spreadsheet models also required abstraction, so maybe we could combine the algorithms and the information systems?

Anyway… I was just debating whether to go with four or five when Tig announced from the front that the people attending this session commonly come up with a list of 24 units and topics - and then panic because there are only 18 half-terms in KS3.

How can it be that some of us see nine bullet points and split them into four or five groups, while others can teach the same content but see it as 24 separate things? Is that why I regularly hear that there's too much content in the Computing curriculum, whereas I teach lots of additional content and still struggle to fill the time?

Could it be that by structuring your course more holistically and reducing the redundancy then you could make life easier for yourself and for the students? There'd be less content for you to try to cram in, and fewer concepts for the students to think about.

You could create a scheme of work that's more like a Venn diagram than a list of topics and then start with the overlapping sections. You can recap the common parts as you visit overlapping topics for some "retrieval practice" or "mastery".

It would be nice if we could take this idea a bit further. Early in my teaching career, I was explaining flowcharts to a KS3 ICT class when someone put up their hand and said "We've done this in DT!" Then someone else put up their hand and said "We did it in English too!". We often don't realise that other subjects are teaching the same ideas - and that's just an example of something that was exactly the same in three different subjects.

Back in the summer, I observed a number of lessons for the annual appraisal cycle. On the same day I watched a science lesson in which students were balancing chemical equations and another in which students were adding fractions with different denominators. On a surface level those two things appear to be different, but at a deeper level they are the same - they're both examples of proportional thinking and basically require the same skills.

I see this in other things that I teach. The range of binary values idea that I mentioned above is also essentially the same idea as "sample spaces" and combinations in probability, which is also the same as counting in binary, both of which can be done with nested loops.

Wouldn't it be nice if we could all see those links across the whole curriculum and reduce the load even further for the students? It would be nicer still if the students spotted those links for themselves, of course, but that's probably expecting too much in the early stages. Bloom's Taxonomy is out of fashion these days, but it still seems intuitive that you have to know something before you can understand it.

When I first heard that Welsh schools are going to blur the boundaries between subjects I was sceptical, but on reflection it would fit in with this idea. I'll be interested to see how they implement it and who ends up teaching which key concepts, but it's an idea that could have merit.

I think it's also an idea that would meet with resistance here, but if you're revising the curriculum within your subject this spring you might find that letting go of the idea of "units" makes you feel like you have less to do next year.

This blog was originally written in January 2024.