An Investigation Into Secondary School Students' Debugging Behaviour in Python

TL;DR

This study examines how 12-14-year-old students debug Python code, revealing common ineffective strategies and barriers, and suggests teaching systematic debugging and improving programming environments.

Contribution

It provides a detailed analysis of secondary students' debugging behaviors in Python, identifying key barriers and proposing educational and tool-based improvements.

Findings

Most students resolved some errors but often used ineffective strategies.

Students frequently added errors, reverted fixes, and repeated runs without reflection.

Four main barriers to effective debugging were identified: fragile knowledge, lack of systematicity, syntax issues, and emotional factors.

Abstract

Background and context: Debugging is a significant and often frustrating challenge for beginner programmers. Understanding students' debugging behaviours and strategies can help to identify common difficulties and inform approaches for alleviating these. Currently, there are limited studies of school students' debugging behaviour in a text-based programming language, a medium through which millions are learning to program. Objectives: In this paper, we investigate the debugging behaviour of 12-14-year-old students learning Python through a lesson-long classroom study. Method: We collected program snapshots from 73 students' attempts at a set of Python debugging exercises in an online code editor. Through qualitative content analysis of these snapshots, we developed a granular categorisation of the changes students made when debugging. Findings: While most students were able to resolve some errors, most also frequently exhibited ineffective debugging behaviours. Many students added errors through small-scale changes, reverted corrective changes, and repeatedly ran identical programs in quick succession. From the results, we identify four barriers to successful and reliable debugging for students learning a text-based programming language: fragile knowledge, a lack of systematicity and reflection, the syntax barrier, and dynamics of emotions and attitudes. Implications: This paper highlights some of the difficulties that secondary school students have when debugging in Python. We recommend that school teachers explicitly teach a systematic approach to debugging and discourage the use of ineffective debugging behaviours, and that programming environments should contain features that facilitate successful debugging.