Debugging: the good, the bad, and the quirky -- a qualitative analysis of novices' strategies

ABSTRACT

A qualitative analysis of debugging strategies of novice Java programmers is presented. The study involved 21 CS2 students from seven universities in the U.S. and U.K. Subjects "warmed up" by coding a solution to a typical introductory problem. This was followed by an exercise debugging a syntactically correct version with logic errors. Many novices found and fixed bugs using strategies such as tracing, commenting out code, diagnostic print statements and methodical testing. Some competently used online resources and debuggers. Students also used pattern matching to detect errors in code that "just didn't look right". However, some used few strategies, applied them ineffectively, or engaged in other unproductive behaviors. This led to poor performance, frustration for some, and occasionally the introduction of new bugs. Pedagogical implications and suggestions for future research are discussed.

REFERENCES

• 1: Marzieh Ahmadzadeh , Dave Elliman , Colin Higgins, An analysis of patterns of debugging among novice computer science students, Proceedings of the 10th annual SIGCSE conference on Innovation and technology in computer science education, June 27-29, 2005, Caparica, Portugal
• 2: M. Ducassé , A.-M. Emde, A review of automated debugging systems: knowledge, strategies and techniques, Proceedings of the 10th international conference on Software engineering, p.162-171, April 11-15, 1988, Singapore
• 3: Sue Fitzgerald , Beth Simon , Lynda Thomas, Strategies that students use to trace code: an analysis based in grounded theory, Proceedings of the 2005 international workshop on Computing education research, p.69-80, October 01-02, 2005, Seattle, WA, USA [doi>10.1145/1089786.1089793]
• 4: S. Fitzgerald, G. Lewandowski, R. McCauley, L. Murphy, B. Simon, L. Thomas and C. Zander. Debugging: Finding, Fixing and Flailing -A multi-institutional study of novice debuggers. Forthcoming in Computer Science Education - Special Issue on Debugging, 18(2), June 2008.
• 5: Gould. Some psychological evidence on how people debug computer programs. International J. of Man-Machine Studies, 7(1), pp. 151--182, 1975.
• 6: L. Gugerty , G. Olson, Debugging by skilled and novice programmers, Proceedings of the SIGCHI conference on Human factors in computing systems, p.171-174, April 13-17, 1986, Boston, Massachusetts, United States
• 7: I. Katz and J. Anderson. Debugging: An analysis of bug location strategies. Human-Computer Interaction, 3(4):351--399, 1987.
• 8: Claudius M. Kessler , John R. Anderson, A model of novice debugging in LISP, Papers presented at the first workshop on empirical studies of programmers on Empirical studies of programmers, p.198-212, June 1986, Washington, D.C., United States
• 9: Robert McCartney , Anna Eckerdal , Jan Erik Mostrom , Kate Sanders , Carol Zander, Successful students' strategies for getting unstuck, Proceedings of the 12th annual SIGCSE conference on Innovation and technology in computer science education, June 25-27, 2007, Dundee, Scotland
• 10: McCauley, S. Fitzgerald, G. Lewandowski, L. Murphy, B. Simon, L. Thomas and C. Zander. Debugging: A review of the literature from an educational perspective. Forthcoming in Computer Science Education -- Special Issue on Debugging, 18(2), June 2008.
• 11: Murthi Nanja , Curtis R. Cook, An analysis of the on-line debugging process, Empirical studies of programmers: second workshop, Ablex Publishing Corp., Norwood, NJ, 1987
• 12: D. N. Perkins , Fay Martin, Fragile knowledge and neglected strategies in novice programmers, Papers presented at the first workshop on empirical studies of programmers on Empirical studies of programmers, p.213-229, June 1986, Washington, D.C., United States
• 13: Vessey. Expertise in debugging computer pro-grams: A process analysis. International J. of Man-Machine Studies, 23, pp. 459--494, 1985.

INDEX TERMS

Primary Classification:
  K. Computing Milieux
  K.3 COMPUTERS AND EDUCATION
      K.3.2 Computer and Information Science Education
          Subjects: Computer science education

General Terms:
Human Factors

Keywords:
debugging, novice programming, pedagogy, strategies