Models of Wikipedia Dynamics

Ed H. Chi(joint work with

Bongwon Suh, Gregorio Convertino, Peter Pirolli)

Area ManagerAugmented Social Cognition Area

Intelligent Systems Laboratory

Total Edits Changes

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Total Active Editors

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Logistic Model (k=carrying capacity)

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A hypothetical logistic Lotka-Volterra population growth model bounded by a limit K.

P = population sizer = growth rateK = carrying capacity

Logistic Growth Model

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A Revised Logistic Growth Model

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Deeper Analysis based on Editor Classes

Edit Activities by Editor Class

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Edit Activities by Editor Class

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Resistance (Revert Ratio)

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Population shift

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Population Shifts (log scale)

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Population Shift (%)

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Admin Changes and Protection Measures

Admin changes

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User Blocks

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Page Protection

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Pages Survived vs. Deleted (in thousands)

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Key takeaways• Wikipedia can be viewed as an in-vivo,

unprecedented experiment on knowledge co-creation.

• Editing activity changing– Moved from exponential growth to logistic growth

• Population dynamic changing– Revert resistance different for lower class editors– Middle class being squeezed– Pyramid structure important?

• Protection measures correlate with activity