Conway's law is an adage named after computer programmer Melvin Conway, who introduced the idea in 1967. It was first dubbed Conway's law by participants at the 1968 National Symposium on Modular Programming. It states that
"organizations which design systems ... are constrained to produce designs which are copies of the communication structures of these organizations."— M. Conway
The law is based on the reasoning that in order for a software module to function, multiple authors must communicate frequently with each other. Therefore, the software interface structure of a system will reflect the social boundaries of the organization(s) that produced it, across which communication is more difficult. Conway's law was intended as a valid sociological observation, although sometimes it's used in a humorous context.
Al Shalloway's corollary to Conway's Law: When development groups change how their development staff are organized, their current application architecture will work against them.
Eric S Raymond, an open-source advocate, restated Conway's law in The New Hacker's Dictionary, a reference work based on the Jargon File. The organization of the software and the organization of the software team will be congruent, he said. Summarizing an example in Conway's paper, Raymond wrote: "If you have four groups working on a compiler, you'll get a 4-pass compiler."
"If the parts of an organization (e.g., teams, departments, or subdivisions) do not closely reflect the essential parts of the product, or if the relationship between organizations do not reflect the relationships between product parts, then the project will be in trouble... Therefore: Make sure the organization is compatible with the product architecture."
One can also see the impact of Conway's Law in design of corporate websites. Nigel Bevan, a usability expert, stated in 1998: "Organisations often produce web sites with a content and structure which mirrors the internal concerns of the organisation rather than the needs of the users of the site." A similar effect may be found when websites undergo design by committee.
Evidence in support of Conway's law has been published by a team of MIT and Harvard Business School researchers, who found "strong evidence to support [what they term the equivalent]… mirroring hypothesis", and that "significant differences in [product] modularity" were "consistent with a view that distributed teams tend to develop more modular products".
Additional and likewise supportive case studies of Conway's law have been conducted by Nagappan, Murphy and Basili at the University of Maryland in collaboration with Microsoft, and by Syeed and Hammouda at Tampere University of Technology, in Finland.
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- Conway, Melvin E. (April 1968), "How do Committees Invent?", Datamation, 14 (5): 28–31, retrieved 2015-04-10
- Eric S. Raymond (October 1996). The New Hacker's Dictionary - 3rd Edition. ISBN 978-0-262-68092-9.
- Eric S. Raymond, Conway's Law, retrieved 2012-06-18
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- "Usability Issues in Web Site Design" (PDF). Retrieved 30 March 2015.
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- Nachiappan Nagappan, Brendan Murphy & Victor Basili, 2008, "The Influence of Organizational Structure On Software Quality: An Empirical Case Study," ACM TechReport MSR-TR-2008-11, see , accessed 9 March 2015.
- M. M. Mahbubul Syeed & Imed Hammouda, 2013, "Socio-technical Congruence in OSS Projects: Exploring Conway’s Law in FreeBSD," In Open Source Software: Quality Verification, Part I (Etiel Petrinja, Giancarlo Succi, Nabil El Ioini & Alberto Sillitti, Eds.), IFIP Advances in Information and Communication Technology Volume 404 (Proceedings of the 9th IFIP WG 2.13 International Conference, OSS 2013, Koper-Capodistria, Slovenia, June 25–28, 2013), pp. 109-126, Berlin:Springer, DOI 10.1007/978-3-642-38928-3_8, ISBNs 9783642389276 and 9783642389283, see , accessed 9 March 2015.
- Alan MacCormack, John Rusnak & Carliss Baldwin, 2012, "Exploring the Duality between Product and Organizational Architectures: A Test of the 'Mirroring' Hypothesis," Research Policy 41:1309–1324 [earlier Harvard Business School Working Paper 08-039], see , accessed 9 March 2015.
- Lise Hvatum & Allan Kelly, Eds., "What do I think about Conway's Law now? Conclusions of a EuroPLoP 2005 Focus Group," European Conference on Pattern Languages of Programs, Kloster Irsee, Germany, January 16, 2006, see , addressed 9 March 2015.
- Lyra Colfer & Carliss Baldwin. "The Mirroring Hypothesis: Theory, Evidence and Exceptions." Harvard Business School Working Paper, No. 16-124, April 2016. (Revised May 2016.) See , accessed 2 August 2016.