Introducing Code Quality at CS1 Level: Examples and Activities

Characterising code quality is a challenge that was addressed by a previous ITiCSE Working Group (Börstler et al., 2017). As emerged from that study, educators, developers, and students have different perceptions of the aspects involved. The perception of code quality by CS1 students develops from the feedback they receive when submitting practical work. As a consequence of increasingly large classes and the widespread use of autograders, student code is predominantly assessed based on functional correctness, emphasising a machine-oriented perspective with scarce or no feedback given about human-oriented aspects of code quality. Such limited perception of code quality may negatively impact how students understand, create, and interact with code artefacts. Although Börstler et al. concluded that "code quality should be discussed more thoroughly in educational programs", the lack of materials and time constraints have slowed down progress in that regard.
The goal of this Working Group is to support CS1 instructors who want to introduce a broader perspective on code quality in their classroom, by providing a curated list of examples and activities suitable for novices. In order to achieve this goal, we have extracted from the CS education literature a range of examples and activities, which have then been analysed and organised in terms of code quality dimensions. We have also mapped the topics covered in those materials to existing taxonomies relevant to code quality in CS1. Based on this work, we provide: (1) a catalogue of examples that illustrates the range of quality defects that could be addressed at CS1 level; and (2) a sample set of activities devised to introduce code quality to CS1 students. These materials have the potential to help educators address the subject in more depth.