The Social Structure of Open Source Software Development Authors: - - PowerPoint PPT Presentation

The Social Structure of Open Source Software Development

Authors: Kevin Crowston and James Howison Presented by Bill Shenk

What is social structure?

• Control
• Coordination
• Socialization
• Continuity

Why study social structure for OSSE?

“little is known about how people in these communities coordinate software development … or about what software processes, work practices, and

• rganizational contexts are necessary to their

success.”

Walt Scacchi, “Software Development Practices in Open Software Development Communities: A Comparative Case Study”, 2002

Why does this matter?

Understanding social structure can help with:

• Development planning
• Predictable relationships between code structure and

social structure

• Risk management
• Team members that are vital to the success of a project

What's important when studying social structure?

• Individuals

– Group size: small, large? constant, growing, shrinking?

• Their actions

– How is the work divided? Who contributes what?

• Their interactions

– Who talks to whom, how often, where? – Is the communication funneled somehow?

Centralization and decentralization: Development

• Actions: code is written
• Centralized: a small core group of code contributors

– cathedral

• Decentralized: contributions from a larger portion of

project individuals – bazaar

Centralization and decentralization: Communication

• Interactions between project members (via email, IM,

wiki, bug-tracking, etc.)

• Centralized: small group who speak to the larger

group, and large group talks only to small group

• Decentralized: project members speak to each other

as a whole

Decentralized development and communication

Raymond (1998), Kuwabara (2000), Cox (1998) suggest that most OSS projects are decentralized in development, communication, or both

• Decentralized development and planning are a good

indication of decentralized communication

• “decentralized development” surrounded in “clamor

… anyone is welcome – the more people, the louder the clamor, the better it is.” - Kuwabara (2000)

• The more the merrier!

Decentralized communication and OSS

Alan Cox argues that bazaar projects can lead to “clique” formation

• Linux for 8086: noise from inexperienced

programmers prompted the core developers to form a secluded group

• Discussions should focus on existing code rather

than opinions and ideas, avoid “town councilors”

Centralized communication and OSS

• Centralized social structures can sometimes lead to

“ownership” of a project

• Informal ownership often goes to founding

member(s) – e.g., Linux

• Raymond (1998) believes that some centralization is

vital to OSS success

Authors' Study

• Examined communication centralization during bug-

fixing stage

• Chosen because there are a “microcosm of

coordination problems” (Crowston 1997) and collaboration across many individuals and roles

• Data taken from SourceForge through spiders and

parsers

• Criteria: at least seven developers with at least 100

bugs per project from relatively active projects

How the data was analyzed

• SourceForge ID was used as an individual's identifier
• Each message tied to a bug counts as one

interaction from one sender to another sender, starting with reporter

• 23% of messages were sent anonymously,

considered extraneous and therefore not utilized (“nobody interactions”)

Some raw figures

• 120 projects (out of 50,000 at the time) were

analyzed that fit criteria and had available bug- tracking data

• 61,068 bug reports, avg. of 509 per project – bugs

with at least one reply were counted

• 14,922 total unique users (posters) with avg. of 140

users per project

Centralization scores

• Central project individuals are those who send and

receive greater number of messages

• Members who send messages (out-degree centrality)

are measured for centrality

• In a very centralized project, a single individual will

have a high out-degree; in decentralized, no one person stands out

Pretty graph – interaction plot

Figure 5 – openrpg

Pretty graph – interaction plot

Figure 9 – curl, centralization = 0.922

Pretty graph – interaction plot

Figure 10 – squirrelmail, centralization = 0.377

Distribution

Figure 8 – centralization scores for projects

Project size vs. centralization

• Authors discovered large projects are typically less

centralized

• Possible interpretation: in a large project, it is difficult

for a single individual to fix every bug

• Growing projects lead to modularity and formation of

smaller groups

What does it all mean?!

• Data and graphs show that the bug-tracking

communication, on the whole, was neither centralized nor decentralized

• Average centralization: 0.56 ± 0.20

Questions & Further Analysis

• Projects that changed leaders?

(centralized → decentralized)

• Posters with high out-degree might be verbose/unclear

and score artificially higher?

• Mailing list communication centralization also measured

for 52 projects showed similar results. What about other ways of measuring communication centralization?

• Communication centralization vs. development

centralization? Would it show similar results?

Thank you!