The structure of social collaboration on WikipediaSorin Adam Matei, Associate Professor of Communication, Purdue Usmatei@purdue.eduDavid Braun, Research Scientist, Envision Lab, Purdue Udbraun@purdue.eduHoriaPetrache, Assistant Professor of Physics, IUPUIhpetrach@iupui.eduPresented at Wikimania, 2009Buenos Aires, ArgentinaAugust 25-28 2009http://wikimania2009.wikimedia.org/wiki/Proceedings:132

2005: A Wikipedian explains Wikipedia as Wisdom of CrowdsThe basic premise [of Wisdom of Crowds] that crowds of relatively ignorant individuals make better decisions than small groups of experts. I'm sure everyone here agrees with this as Wikipedia is run this way...Wikipedia displays emergent properties because each article is better than the contribution of each individual. Similarly, ants display emergence because an ant colony can accomplish things that each individual ant cannot even conceive.

Implied ideaFine grained, micro contributions, independent and decentralized and maybe equal lead to articles that are better than what each contributor can write

As expressed in this Wikipedia-l postI imagine Wikipedia as a massive, active swarm intelligence, supplemented by small roving groups of active editors who admire consistency, elegance, and reasoned discourse. (not unlike certain models of how the brain works :) The swarm does the bulk of the writing, especially finding and providing current facts, starting new articles, and adding neglected POVs. The roving groups are sensitive to dozens of policy pages, and implement them as they rove... they also take on large projects, one at a time, and try to implement certain changes across thousands of pages at once.

To which “Jimbo” (Wales) answersI should point out that I like Suroweicki'sthesis just fine, it's just that I'm not convinced that "swarm intelligence" is very helpful in understanding how Wikipedia works -- in fact, it might be an impediment, because it leads us away from thinking about how the community interacts in a process of reasoned discourse.

Jimbo concludesMy research (conducted in December) showed that half the edits by logged in users belong to just 2.5% of logged in users.

Does the 80/20 applies?Power-law curves are all over the real world …Adar and Huberman (2000) found 50% of the content on Gnutella is provided by 1% of the users, O'Mahonyand Ferraro (2003) found the curve in the Debian dev key ring, Moon and Sproul (2002) on the Linux Kernel list, Briggs et al. (1997) in group support systems, Krogh, Spaeth and Lakhani (2003) in Freenet.(By another participant to the 2005 discussion)

What would the 80/20 rule mean?Extreme inequality? Elitism?Structured collaboration?Interactive exchanges between groups of individuals?

Previous researchWikipedia contributions, in all languages, have become more skewed in favor of a small group of editors and old time users (Ortega et al., 2005)

Top contributors dominate edits and no words contributed

Our approachIncrease in inequality => higher level of structurationIncreasing division of laborFrom diffuse collaboration to structured collaborationEmergence of bureaucracyEmergence of adhocracyGroups of individuals that become article stewards

Social entropy and structurationSocial EntropyAs system become organized (biased) their entropy decreasesEntropy is a measure of meaningful organization

Entropy and organizationMeaningful messages use words and letters in uneven mannerSymbol distribution in meaningful messages is unevenInformation (and social) entropy are measures of organization and meaningAs collaboration becomes more biased, the group becomes more organized

Shannon’s formulawhere the sum is over all users i, and is the fractional contribution of user i. We allow p and S and to be functions of time (t).

Shannon’s forumal explainedSocial entropy reflects how uneven and lacking in diversity a group/system process is10 users and 100 contributions, each contributing 10 edits to a Wikipedia article => entropy reaches its highest level1 contributor contributes all, entropy at the lowest value

Analytic strategyDownloaded latest available dumpTrouble with unzipping (dump corrupted)Extracted 792,654 registered users234,798 articlesCalculated number of times individuals contributed to each article and how many words have they contributed (not completely finalized)

Red: observed entropy valuesOrange: fit curve (takes into account the spread of valuesDotted: Maximum entropy, wisdom of crowds ceilingln(x)Intervention entropyBasic plot: Entropy increases for the first @500 interventions, then levels off….Intervention number (events)

Red: observed entropy values

Orange: fit curve (takes into account the spread of values

Dotted: Maximum entropy, wisdom of crowds ceiling

Red: observed entropy valuesOrange: fit curve (takes into account the spread of valuesDotted: Maximum entropy, wisdom of crowds ceilingln(x)Intervention entropyIntervention number (events)Logged plot: Average article entropy increasingly and monotonously diverges from the “wisdom of the crowds” ceiling. Wikipedia becomes “cooler” and more and more structured ….

Red: observed entropy values

Orange: fit curve (takes into account the spread of values

Dotted: Maximum entropy, wisdom of crowds ceiling

Standard deviation/ Int. EntropyAfter the 500th intervention the coefficient of variation (StDev/Mean) becomes constant; all articles tend to behave within the same limits of variability for the next 9,500 iterationsn-1/2ratioIntervention number (events)

What remains to be doneEntropy decreases, Wikipedia “hardens”Does it become more structured? In what way?Will analyze degree of structuration measuring structure of coedits (network) analysisExpectation: as entropy decreases, network structures become more hierarchical can inflexible (less degrees of freedom)Will analyze distribution of collaboration across formal and informal rolesWho are the nodes of collaborationWhat is their contribution to cooling and hardening Wikipedia