Identifying threshold concepts
Researcher Peter Davies suggests two methods for identifying threshold concepts (helloworld.cc/davies2006). The first approach includes the engagement of two distinct disciplines, and specifically, the views in which these disciplines examine the same situation. The second approach, which is mostly used in the current literature, such as Janet and Nathan Rountree’s 2009 paper (helloworld.cc/rountree2009), suggests that to identify threshold concepts, the researcher should concentrate on people inside and outside of the community; that is, on the different ways in which students and experts experience the situation.
The Raspberry Pi Foundation has defined threshold concepts within computing education in a similar way. When deciding whether or not a concept is a threshold concept, we at the Foundation use the following criteria:
A threshold concept should be relevant to two or more topic areas within the subject (portability)
A threshold concept should be revisited from a teaching and learning perspective several times across different ages and stages of learning (buildability)
In some subjects, threshold concepts are easy to identify. Consider young readers, for example. They are initially taught the threshold concept of phonics, which introduces them to the alphabet and letter sounds, which they can blend into simple and then more complex words. They are then introduced to the threshold concept that not all words are spelled as they sound.
The same is true in computing, or at least some elements of it. In programming, in the Teach Computing Curriculum, we introduce four threshold concepts, one per year group from ages seven to eleven: sequence, repetition, selection, and variables (helloworld.cc/tcc). By isolating these four concepts, you can introduce each progressively, and gradually develop an understanding of each one. We have found that there is a broad consensus that this order is appropriate at this age range.
In some areas of computing, however, threshold concepts are not as widely agreed on or accepted. The content and curriculum team at the Raspberry Pi Foundation has picked out ‘Creating media’ as an example of a strand of computing that could benefit from an approach more based on threshold concepts. At a high level, we have identified a number of commonalities when working with computer-based media. Whether you’re creating a presentation or producing a video, you will need some understanding of:
Files
Text
Images
Audio/video
Animation
Layers
Objects
Hyperlinks
Preview
Templates
There may be more concepts than this; research in this area of computing education is underdeveloped, so we aim to narrow down to the key concepts. Some of the items in the list above can be considered more skills-based than others, for example file management. But there are some clear concepts that can be considered as thresholds to further learning:
Layers
Objects
Hyperlinks
Preview
Placeholders
Templates/styles (global application)
Colour accessibility
Once identified, these concepts can be introduced progressively across a range of media, teaching students concepts and skills that are transferable across different areas of the computing curriculum. For example, if a student understands layering in desktop publishing, they will be at a significant advantage when they move on to creating vector drawings, as the concept is fundamentally the same in both types of media. This can deliver significant benefits to students across all age ranges:
The identification of threshold concepts accentuates their importance
Skills and concepts can be introduced systematically in one context before being applied to others
The transition between learning stages can be smoother, with less need to recap
Students learn to apply concepts across different curriculum areas
Pedagogical strategies
Now that we have considered how we define and identify threshold concepts, we need to look at the best way of teaching them to learners and the pedagogical strategies that might be most suitable for threshold concepts in the ‘Creating media’ strand of computing. In programming, there is a great deal of research into the best ways of teaching new skills and concepts. Thousands of educators have implemented and iterated strategies such as Use–Modify–Create and Predict–Run–Investigate–Modify–Make (PRIMM). In ‘Creating media’, there is nowhere near as much to go on. So, is there scope to adapt some of the strategies that are so widely used in programming to other areas of the curriculum?
Let’s consider the Use–Modify–Create strategy introduced by researcher Lee and her colleagues, which gives students a structure for learning to program (helloworld.cc/lee2011). At the Use stage, students use an existing program, analysing what it does and how it does it. They then apply this knowledge to modify parts of the program so that it achieves a different outcome, before creating their own program from scratch.
Could a similar approach work in ‘Creating media’? Instead of Use, for example, could students ‘consume’ a particular type of media? Take vector drawings as an example. In isolation, many students will not be familiar with the concept of vector drawings. To familiarise them with it, you could ask learners to edit or adapt a vector graphic so that it suits a different audience or purpose (that is, as part of the Modify stage). This could involve changing the position, order, or colour of objects, but crucially, not creating anything new.
At this point, you could cover threshold concepts associated with layers, objects, and colours, without the added cognitive load of students having to think about creating their own idea. They could then build upon this experience to create a new artefact, with the scaffolding of existing content. It may be that you are actually already doing some of this in your own practice, but having a structure could help you to formalise and standardise your approach.
It is vital that we know how to define, identify, and approach the teaching of threshold concepts in the computing classroom, to ensure that learners can progress and build subsequent skills and concepts successfully. Evidently, there is still work to be done within this area for ‘Creating media’ topics. How could you apply these ideas in your classroom, and are there any other ideas you might be able to weave in?
