Virtually anything can be and is ranked; people, institutions, countries, words, genes. Rankings reduce complex systems to ordered lists, reflecting the ability of their elements to perform relevant functions, and are being used from socioeconomic policy to knowledge extraction. A century of research has found regularities when temporal rank data is aggregated. Far less is known, however, about how rankings change in time. Here we explore the dynamics of 30 rankings in natural, social, economic, and infrastructural systems, comprising millions of elements and timescales from minutes to centuries. We find that the flux of new elements determines the stability of a ranking: for high flux only the top of the list is stable, otherwise top and bottom are equally stable. We show that two basic mechanisms — displacement and replacement of elements — capture empirical ranking dynamics. The model uncovers two regimes of behavior; fast and large rank changes, or slow diffusion. Our results indicate that the balance between robustness and adaptability in ranked systems might be governed by simple random processes irrespective of system details.
Bio:
Gerardo is an assistant professor at the Department of Network and Data Science of Central European University (Austria), visiting researcher at Aalto University (Finland) and UNAM (Mexico), and co-founder at Predify (Mexico). He likes complex systems, networks, computational social science, and data science. Gerardo also writes fiction and co-develop videogames on the side. Find out more on his website at: www.gerardoiniguez.com
If you would like to attend the talk, please sign-up via office@csh.ac.at
Gerardo Iñiguez (CEU) will give a talk on Wednesday, January 18, 2023 at 3 PM in Room 201.