A study by a ITiCSE 2001 working group ("the McCracken Group") established that many students do not know how to program at the conclusion of their introductory courses. A popular explanation for this incapacity is that the students lack the ability to problem-solve. That is, they lack the ability to take a problem description, decompose it into sub-problems and implement them, then assemble the pieces into a complete solution. An alternative explanation is that many students have a fragile grasp of both basic programming principles and the ability to systematically carry out routine programming tasks, such as tracing (or "desk checking") through code. This ITiCSE 2004 working group studied the alternative explanation, by testing students from seven countries, in two ways. First, students were tested on their ability to predict the outcome of executing a short piece of code. Second, students were tested on their ability, when given the desired function of short piece of nearcomplete code, to select the correct completion of the code from a small set of possibilities. Many students were weak at these tasks, especially the latter task, suggesting that such students have a fragile grasp of skills that are a prerequisite for problemsolving.

McCauley, Ren?e, Fitzgerald, Sue, Lewandowski, Gary, Murphy, Laurie, Simon, Beth, Thomas, Lynda and Zander, Carol(2008) 'Debugging: a review of the literature from an educational perspective', Computer Science Education,18:2,67 ? 92This paper reviews the literature related to the learning and teaching of debugging computer programs. Debugging is an important skill that continues to be both difficult for novice programmers to learn and challenging for computer science educators to teach. These challenges persist despite a wealth of important research on the subject dating back as far as the mid 1970s. Although the tools and languages novices use for writing programs today are notably different from those employed decades earlier, the basic problem-solving and pragmatic skills necessary to debug them effectively are largely similar. Hence, an understanding of the previous work on debugging can offer computer science educators insights into how to improve contemporary learning and teaching of debugging and may suggest directions for future research into this important area. This overview of the debugging literature is organized around four questions relevant to computer science educators and education researchers: What causes bugs to occur? What types of bugs occur? What is the debugging process? How can we improve the learning and teaching of debugging? We conclude with suggestions on using the existing literature both to facilitate pedagogical improvements to debugging education and to offer guidance for future research.Peer reviewe

Fitzgerald, Sue, Lewandowski, Gary, McCauley, Ren?e, Murphy, Laurie, Simon, Beth, Thomas, Lynda and Zander, Carol(2008) 'Debugging: finding, fixing and flailing, a multi-institutional study of novice debuggers? Computer Science Education,18:2, 93-116 Special Issue: Debugging by Novice ProgrammersDebugging is often difficult and frustrating for novices. Yet because students typically debug outside the classroom and often in isolation, instructors rarely have the opportunity to closely observe students while they debug. This paper describes the details of an exploratory study of the debugging skills and behaviors of contemporary novice Java programmers. Based on a modified replication of Katz and Anderson's study of novices, we sought to broadly survey the modern landscape of novice debugging abilities. As such, this study reports general quantitative results and fills in the picture with qualitative detail from a relatively small, but varied sample. Comprehensive interviews involving both a programming and a debugging task, followed by a semi-structured interview and a questionnaire, were conducted with 21 CS2 students at seven colleges and universities. While many subjects successfully debugged a representative set of typical CS1 bugs, there was a great deal of variation in their success at the programming and debugging tasks. Most of the students who were good debuggers were good novice programmers, although not all of the good programmers were successful at debugging. Students employed a variety of strategies to find 70% of all bugs and of the bugs they found they were able to fix 97% of them. They had the most difficulty with malformed statements, such as arithmetic errors and incorrect loop conditions. Our results confirm many findings from previous studies (some quite old) - most notably that once students find bugs, they can fix them. However, the results also suggest that some changes have occurred in the student population, particularly an increased use of debugging tools and online resources, as well as the use of pattern matching, which has not previously been reported.Peer reviewe

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A study by a ITiCSE 2001 working group ("the McCracken Group") established that many students do not know how to program at the conclusion of their introductory courses. A popular explanation for this incapacity is that the students lack the ability to problem-solve. That is, they lack the ability to take a problem description, decompose it into sub-problems and implement them, then assemble the pieces into a complete solution. An alternative explanation is that many students have a fragile grasp of both basic programming principles and the ability to systematically carry out routine programming tasks, such as tracing (or "desk checking") through code. This ITiCSE 2004 working group studied the alternative explanation, by testing students from seven countries, in two ways. First, students were tested on their ability to predict the outcome of executing a short piece of code. Second, students were tested on their ability, when given the desired function of short piece of nearcomplete code, to select the correct completion of the code from a small set of possibilities. Many students were weak at these tasks, especially the latter task, suggesting that such students have a fragile grasp of skills that are a pre-requisite for problemsolving.124

This study investigates the relationship between novice programmers' ability to explain code segments and their ability to write code. Results show a strong correlation between ability to correctly answer 'explain in plain English' (EiPE) questions and ability to write code indicating that there are aspects of reasoning about code that are common to both writing code and explaining code. Student explanations were categorized using the Structure of the Observed Learning Outcome (SOLO) taxonomy. The better programmers were more likely to articulate relational aspects of the algorithms. While earlier work also found such a link, the code writing in those earlier studies was done on paper. This is the first such result where the writing component was done with 'hands on' a computer. Our results add further evidence for the existence of an aspect of reasoning about code that is common to both explaining code and writing code, which in turn suggests that a judicious mix of teaching both code skills and code explaining skills may lead to a more effective process by which novices learn to reason about code.

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This paper presents a case study of the use of a repeated single-criterion card sort with an unusually large, diverse participant group. The study, whose goal was to elicit novice programmers' knowledge of programming concepts, involved over