Models of Wikipedia Dynamics Ed H. Chi (joint work with Bongwon Suh, Gregorio Convertino, Peter Pirolli) Area Manager Augmented Social Cognition Area Intelligent Systems Laboratory

Total Edits Changes Intelligent Systems Laboratory

Total Active Editors Intelligent Systems Laboratory

Logistic Model (k=carrying capacity) Intelligent Systems Laboratory A hypothetical logistic Lotka-Volterra population growth model bounded by a limit K. P = population size r = growth rate K = carrying capacity

Logistic Growth Model Intelligent Systems Laboratory

A Revised Logistic Growth Model Intelligent Systems Laboratory

Deeper Analysis based on Editor Classes

Edit Activities by Editor Class Intelligent Systems Laboratory

Edit Activities by Editor Class Intelligent Systems Laboratory

Resistance (Revert Ratio) Intelligent Systems Laboratory

Population shift Intelligent Systems Laboratory

Population Shifts (log scale) Intelligent Systems Laboratory

Population Shift (%) Intelligent Systems Laboratory

Admin Changes and Protection Measures

Admin changes Intelligent Systems Laboratory

User Blocks Intelligent Systems Laboratory

Page Protection Intelligent Systems Laboratory

Pages Survived vs. Deleted (in thousands) Intelligent Systems Laboratory

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

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