Sunday, May 1, 2016

Why not use open source code examples? A Case Study of Prejudice in a Community of Practice

by Ohad Barzilay, Tel Aviv University (
Associate Editor: Christoph Treude (@ctreude)

With so much open source code available online, why do some software developers avoid using it? That was the research question guiding a qualitative grounded-theory study recently published [1]. We analyzed the perceptions of professional software developers as manifested in the LinkedIn online community, and used the theoretical lens of prejudice theory to interpret their answers in a broader context.

We focused on developers’ perception of (re)using code examples - existing code snippets that are used in a new context. Our definition of a code ‘example’ is broad; some of the code examples which appear on the Internet were not written in order to be reused. Code examples may accompany answers on Q&A sites [2], illustrate an idea in an online tutorial, or even be extracted from an open source project [7].

We suggest that developers’ approach with respect to using code examples is dominated by their personality, and affected by concerns such as their community identity, ownership and trust. We find that developers’ perception of such reuse goes beyond the activities and practices, and that some developers associate the use of code examples with negative character. Some of these developers stereotype habitual example users as inferior and unprofessional.

It should be noted that not only human aspects are associated with example usage – there are some other issues involved in this activity such as engineering aspects (e.g. search techniques and tools) and legal issues (e.g. copyright and licensing). These issues are outside of the scope of our discussion; however, we believe that these challenges can be mitigated with proper tools [9], training and organizational support (e.g. leveraging upon social media cues [8], teaching developers which code could they use, and under what circumstances).

Code Writers vs. Copy-and-Paste Monkeys

Some software developers perceive themselves as code writers, and feel strongly about it. Their identity and sometimes even self-esteem are derived from perceiving themselves that way. As suggested by Bewer [5] this may result in the creation of ingroup bias, and can be in turn used as a platform for hate of the outgroup – in this domain, example users. For the code writers (virtual) group, new code is the unit of progress, a sign of productivity (however misleading it may sometimes be). Copying, on the other hand, is perceived as a devalued shortcut – an imitation rather than a creation. In most university courses, the students are not allowed to share their work with fellow students, but are expected to write their own code.

Having ingroup bias often limits boundaries of trust and cooperation [6], which may explain why some developers avoid copy and paste at all cost. They do not trust other programmers enough to take responsibility for and ownership of their code. These programmers find it difficult to understand existing code, they feel that they cannot identify fallacies in someone else's code nor test it thoroughly. They prefer to write the code by themselves and take responsibility for it rather than trust others, and perhaps lose control over their code.

Furthermore, we find that example usage opponents do not conform to organizational goals, and specifically the need for speed. They do not acknowledge the required dexterity and practices for effective example usage, and they aspire to be held in high regard (as opposed to "merely plumbers" [4], suggesting that the essence of the software engineering job boils down to putting the components together and making small non-glorious fixes). After all, some of them might have chosen programming as their profession because of its status.


In a commercial context, revealing implicit prejudice and disarming it may allow developers to leverage further benefit of code reuse, and may improve the collaboration of individuals, teams and organizations. Moreover, prejudice may interfere with achieving organizational goals, or while conducting an organizational change. Some of these concerns may be mitigated by providing a comprehensive ecosystem of tools, practices, training and organizational support [3]. Having the prejudice lens in mind, one may incorporate methods which were proven effective in addressing prejudice in different context (racism, sexism, nationalism) as part of the software engineering management tools.

Finally, this study may also be considered in the broader context of the changing software engineering landscape. The recent availability of information over the Web, and in our context – availability of source code, is challenging the way software is produced. Some of the main abstractions used in the software domain, namely development and construction, do not adequately describe the emerging practices involving pragmatic and opportunistic reuse. These practices favor composing over constructing and finding over developing. In this context, prejudice can be perceived as a reaction to change and an act resulting from fear of the new and unknown.


[1] O. Barzilay and C. Urquhart. Understanding reuse of software examples: A case study of prejudice in a community of practice. Information and Software Technology 56, pages 1613-1628, 2014.
[2] O. Barzilay, C. Treude, and A. Zagalsky. Facilitating crowd sourced software engineering via Stack Overflow. In S. E. Sim and R. E. Gallardo-Valencia, editors, Finding Source Code on the Web for Remix and Reuse, pages 289–308. Springer New York, 2013.
[3] O. Barzilay. Example embedding. In Proceedings of the 10th SIGPLAN symposium on New ideas, new paradigms, and reflections on programming and software, pages 137-144, 2011, ACM.
[4] O. Barzilay, A. Yehudai, and O. Hazzan. Developers attentiveness to example usage. In Human Aspects of Software Engineering, HAoSE ’10, pages 1–8, New York, NY, USA, 2010. ACM.
[5] M. B. Brewer. The psychology of prejudice: Ingroup love and outgroup hate? Journal of social issues, 55(3):429–444, 1999.
[6] S. L. Jarvenpaa and A. Majchrzak. Knowledge collaboration among professionals protecting national security: Role of transactive memories in ego-centered knowledge networks. ORGANIZATION SCIENCE, 19(2):260–276, 2008.
[7] S. E. Sim and R. E. Gallardo-Valencia, editors. Finding Source Code on the Web for Remix and Reuse. Springer, 2013.
[8] C. Treude and M. P. Robillard. Augmenting API documentation with insights from Stack Overflow. Forthcoming ICSE ’16: 38th Int’l. Conf. on Software Engineering, 2016.
[9] A. Zagalsky, O. Barzilay, and A. Yehudai. Example overflow: Using social media for code recommendation. In Proceedings of the Third International Workshop on Recommendation Systems for Software Engineering, pages 38-42, 2012, IEEE Press.

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