Johannes Wachs

Assistant Professor (non-TT)
Vienna Uni. of Economics and Business
Complexity Science Hub Vienna

About Me

I am an assistant professor (non-TT) at the Institute for Data, Process and Knowledge Management of the Vienna University of Economics and Business (WU Wien). I am also affiliated with the Complexity Science Hub. I study social, technical, and economic networks and their effects on society using methods of data and network science.

Previously I was a postdoctoral researcher at the Chair for Computational Social Sciences and Humanities at RWTH Aachen with Markus Strohmaier. My dissertation, supervised by János Kertész at Central European University, was on the application of network methods to the study of corruption. During my PhD I was a visitor at the Oxford Internet Institute, the Hertie School of Governance, and the Hungarian Academy of Sciences.

News and Updates

- New preprint out: "Digital Traces of Brain Drain: Developers during the Russian Invasion of Ukraine" [Arxiv Link].
------ Some early press coverage: [Handelsblatt - DE], [Novaya Gazeta - RU], [Bloomberg - US], [WSJ - US], [New Scientist - US], [Moscow Times - RU], [Fonetech - CZ], [Tygodnik Powszechny - PL].
- The Linux Foundation used our geography of OSS data in their white paper "World of Open Source: Europe Spotlight 2022" - [Link].

Selected Publications

For a full listing, see my [Scholar page].

The Geography of Open Source Software: Evidence from GitHub [Link]

Johannes Wachs, Mariusz Nitecki, William Schueller, and Axel Polleres
Technological Forecasting and Social Change, 2022.
Presentation: [Link]

Evolving collaboration, dependencies, and use in the Rust Open Source Software ecosystem [Link]

William Schueller, Johannes Wachs, Vito D. P. Servedio, Stefan Thurner, & Vittorio Loreto
Nature Scientific Data, 2022.

Agency independence, campaign contributions, and favouritism in US federal government contracting [Link]

Mihaly Fazekas, Romain Ferrali, and Johannes Wachs
Journal of Public Administration Research and Theory, 2022.

How Gamification Affects Software Developers: Cautionary Evidence from a Natural Experiment on GitHub. [Link]

Lukas Moldon, Markus Strohmaier, and Johannes Wachs
IEEE/ACM 43rd International Conference on Software Engineering (ICSE), 2021.
Summary on YouTube: [Link]

Does crowdfunding really foster innovation? Evidence from the board game industry. [Link]

Johannes Wachs and Balázs Vedres
Technological Forecasting and Social Change, 2021.

Inequality is rising where social network segregation interacts with urban topology. [Link]

Gergő Tóth, Johannes Wachs, Riccardo Di Clemente, Ákos Jakobi, Bence Ságvári, János Kertész, and Balázs Lengyel
Nature Communications, 2021.
---- Der Standard (AT): Wie das Stadtbild Ungleichheiten verstärkt.
---- le Scienze (IT): Il peso della geografia urbana sulle disparità tra cittadini.
---- (HU): Bár az iWiW halott, az adatbázisából kutatják, miként csökkenthetők az egyenlőtlenségek.
---- UPI (EN): For more equitable cities, researchers say to keep social networks intact.
---- Qubit (HU): A rég halott iWiW kincset érő adatain mutatták ki, hol nőhet az egyenlőtlenség Magyarországon.

Writer movements between news outlets reflect political polarization in media. [Link]

Nick Hagar, Johannes Wachs, and Emőke-Ágnes Horvát
New Media & Society, 2021.
---- Der Tagesspiegel (DE): Journalistische Filterblasen.
---- Niskanen Center Science of Politics Podcast (EN): How the Media Economy Drives Political News.
---- RQ1 (EN): How the pandemic (sort of) changed our news habits.

A network approach to cartel detection in public auction markets. [Link]

Johannes Wachs and János Kertész
Scientific Reports, 2019.

Gender Differences in Participation and Reward on Stack Overflow. [Link]

Anna May, Johannes Wachs, and Aniko Hannak
Empirical Software Engineering, 2019.

Social capital predicts corruption risk in towns. [Link]

Johannes Wachs, Taha Yasseri, Balázs Lengyel, and János Kertész
Royal Society Open Science, 2019.

Policy Papers

Gender in European public procurement: Extent, distribution, and impacts. [Link]

Mihaly Fazekas, Yuliia Kazmina, and Johannes Wachs
European Bank for Reconstruction and Development (EBRD) Research Paper, 2020 .

Grants and Prizes

2021-2024: Crisis Response and Intervention Supported by Semantic Data Pooling (CRISP), supported by the FFG's "ICT of the Future" program
October 2020: Our team won the IMF Anti-Corruption Challenge!
2020-2021: Geography of Open Source Software, supported by the City of Vienna-WU Jubilee Fund
2020-2021: Data Set Re-Use, supported by the WU Projects fund


Applied Data Science: Computational Social Science, Vienna University of Economics and Business, repeating
Research Praktikum, RWTH Aachen Winter Semester 2019-20
Social Data Science, course instructor, RWTH Aachen Winter Semester 2019-20
Social Networks, course instructor, RWTH Aachen Summer Semester 2019
Using Big Data for social science research, teaching assistant, CEU Spring 2017
Data Mining, course instructor, AIT Fall 2016
Scientific Python, teaching assistant, CEU Fall 2016, 2017

Selected Student Theses:
--- Philip Grawatsch-Pollhammer, Collaborative Networks in Creative Industries: The Case of Tatort. Bachelor's Thesis, WU Wien, 2022. [PDF]
--- Jeremias Brändle, Analysing the Impact of Corruption on Innovation Performance in European Regions. Bachelor's Thesis, WU Wien, 2021. [PDF]
--- Lukas Moldon, Sending signals in open source: Evidence from a natural experiment. Bachelor's Thesis, RWTH Aachen, 2020. [PDF]
--- Timur Bachschi, From Asking to Answering: Social and Structural Aspects of Contributing to Stack Overflow. Bachelor's Thesis, RWTH Aachen, 2020. [PDF]


PhD Network Science, summa cum laude, Central European University (2019)
MS Applied Mathematics with distinction, Central European University (2012)
BS Mathematics, BS Economics, cum laude, Tulane University (2009)


johanneswachs at gmail dot com