Carol Zander

Putting threshold concepts into context in computer science education

This paper describes Threshold Concepts, a theory of learning that distinguishes core concepts whose characteristics can make them troublesome in learning. With an eye to applying this theory in computer science, we consider this notion in the context of related topics in computer science education.

Can graduating students design software systems

This paper examines software designs produced by students nearing completion of their Computer Science degrees. The results of this multi-national, multi institutional experiment present some interesting implications for educators.

Debugging: a review of the literature from an educational perspective

This 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.

Debugging: finding, fixing and flailing, a multi-institutional study of novice debuggers

Debugging 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 Andersons 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.

Pair programming in education: a literature review

This article provides a review of educational research literature focused on pair programming in the undergraduate computer science curriculum. Research suggests that the benefits of pair programming include increased success rates in introductory courses, increased retention in the major, higher quality software, higher student confidence in solutions, and improvement in learning outcomes. Moreover, there is some evidence that women, in particular, benefit from pair programming. The literature also provides evidence that the transition from paired to solo programming is easy for students. The greatest challenges for paired students appear to concern scheduling and partner compatibility. This review also considers practical issues such as assigning partners, teaching students to work in pairs, and assessing individual contributions, and concludes with a discussion of open research questions.

Debugging From the Student Perspective

Learning to debug is a difficult, yet essential, aspect of learning to program. Students in this multi-institutional study report that finding bugs is harder than fixing them. They use a wide variety of debugging strategies, some of them unexpected. Time spent on understanding the problem can be effective. Pattern matching, particularly at the syntactic level, is an important technique for beginners. The Web has emerged as an obvious first place to look for similar examples. Lack of Web materials at an appropriate beginner level leads to flailing. Hypothesizing about the cause of bugs is an underdeveloped skill.

Games: good/evil

In this special session we present arguments for and against a game-centric computing curriculum. To highlight the issues and ensure equal time for arguments on either side, our session is staged as a debate with three speakers on each side. Our audience is educators and educational researchers interested in the role of game development in the CS curriculum.

Threshold concepts and threshold skills in computing

Threshold concepts can be used to both organize disciplinary knowledge and explain why students have difficulties at certain points in the curriculum. Threshold concepts transform a students view of the discipline; before being learned, they can block a students progress. In this paper, we propose that in computing, skills, in addition to concepts, can sometimes be thresholds. Some students report finding skills more difficult than concepts. We discuss some computing skills that may be thresholds and compare threshold skills and threshold concepts.

Liminal spaces and learning computing

‘Threshold concepts’ are concepts that, among other things, transform the way a student looks at a discipline. Although the term ‘threshold’ might suggest that the transformation occurs at a specific point in time, an ‘aha’ moment, it seems more common (at least in computing) that a longer time period is required. This time period is referred to as the ‘liminal space’. In this paper, we summarise our findings concerning how computing students experience the liminal space and discuss how this might affect teaching. Most of our findings so far relate to software engineering. As it is likely that similar liminal spaces occur in other engineering disciplines, these findings have relevance across engineering education.

Categorizing student software designs: Methods, results, and implications

This paper examines the problem of studying and comparing student software designs. We propose semantic categorization as a way to organize widely varying data items. We describe how this was used to organize a particular multi-national, multi-institutional dataset, and present the results of this analysis: most students are unable to effectively design software. We examine how these designs vary with different academic and demographic factors, and discuss the implications of this work on both education and education research.