Aniko Hannak

Assistant Professor
Department of Informatics
University of Zurich
+41 44 635 43 18

hannak@ifi.uzh.ch
Aniko Hannak

I am an Assistant Professor at the computer science department of the University of Zürich. I received my PhD from the College of Computer & Information Science at Northeastern University advised by Alan Mislove and David Lazer.

Broadly, my work investigates a variety of content serving websites such as Search Engines, Online Stores, Job Search Sites or Freelance Marketplaces. In this quickly changing online ecosystem companies track users' every move and feed the collected data into big data algorithms in order to match them with the most interesting, most relevant content. Since these algorithms learn on human data they are likely to pick up on social biases and unintentionally reinforce them. In my PhD work I created a methodology called Algorithmic Auditing which tries to uncover the potential negative impacts of large online systems. Examples of such audits include examining the "Filter Bubble effect" on Google Search, online price discrimination or detecting inequalities in online labor markets.

For my detailed resume please see my CV.

And here is my PhD thesis (I promise it is easy to read!)

News

  • Join me as a Postdoc in my journey in Zurich! See the call here. If you have any questions about the application, don't hesitate to reach out!
  • Hiring a PhD student, see the call here. If you have any questions about the application, don't hesitate to reach out!
  • StackOverflow changes its reward system based on our paper! Feels amazing when our work results in real-world impact!
  • Starting a new job as an Assistant professor at the University of Zurich. Looking forward to building the Social Computing Group and eating a lot of cheese :)
  • Our paper about gender differences in participation on Stack Overflow was accepted to Empirical Software Engineering! PDF coming soon!
  • Three presentations and a best presentation award at the European Symposium on Societal Challenges in London.
  • Check out the awesome conference we organized on Gender and Success.
  • I was invited to give a keynote talk at CmpleNet in Dubrovnik. See my slides here.

Current Projects

Measuring Bias in Online Labor Markets

Labor economy has been through a lot of structural changes in the past years. People use various online services to find employment, advertise freelance services, collaborate on projects, outsource work, etc. These online sites offer innovative mechanisms for organizing employment or hiring processes and may alter many of the social forces known to cause social inequality in traditional labor markets. While policies in the traditional labor economy protecting people in the labor market have been developed over hundreds of years, we are at the early stages of this process in the online context. Paradoxically, while meaningful policy making requires a good understanding of the mechanisms that create or reinforce inequalities, without regulations reinforcing audits or some form of transparency, it is very difficult to learn about these systems. We combine a variety of methods, including online data collection and empirical analysis, online and field experiments, and survey base data collection.

Gender Bias on Stack Overflow

Programming is a valuable skill in the labor market, making the underrepresentation of women in computing an increasingly important issue. Online question and answer platforms serve a dual purpose in this field: they form a body of knowledge useful as a reference and learning tool, and they provide opportunities for individuals to demonstrate credible, verifiable expertise. Issues, such as male-oriented site design or overrepresentation of men among the site’s elite may therefore compound the issue of women’s underrepresentation in IT. In this project we audit the differences in behavior and outcomes between men and women on Stack Overflow, the most popular of these Q&A sites. We investigate how inequalities known from social sciences manifest in online communities and their root causes.

Simulating income inequality in Ride-Sharing

As they grow in popularity, ride-hailing and food-delivery services such as Uber, Lyft, Ola or Foodora are quickly transforming urban transportation ecosystems. Despite their potential to democratize the labor market, these services are often accused of fostering unfair working conditions and low wages. In this project, we investigate the effect of algorithm design decisions on wage inequality in ride-hailing platforms. Using a simulation approach, we can overcome the difficulties stemming from both the complexity of transportation systems and the lack of data and algorithmic transparency. We calibrate our model based on empirical data, including conditions about locations of drivers and passengers, traffic, the layout of the city, and the algorithm that matches requests with drivers. Then we evaluate the output of the simulation under various external conditions.

Publications

Papers

  • Gender Differences in Participation and Reward on Stack Overflow
    • Anna May,
    • Johannes Wachs,
    • Aniko Hannak

    Empirical Software Engineering, 2019

  • And Now for Something Completely Different: Visual Novelty in an Online Network of Designers
    • Johannes Wachs,
    • Balint Daroczy,
    • Aniko Hannak,
    • Katinka Pall,
    • Christoph Riedl

    Proceedings of the 10th ACM Conference on Web Science (WebSci'18), Amsterdam, May, 2018.

  • Investigating the Impact of Gender on Rank in Resume Search Engines
    • Le Chen,
    • Aniko Hannak,
    • Ruijin Ma,
    • Christo Wilson

    In Proceedings of ACM Human Factors in Computing Systems (CHI 2018). Montreal, Canada, April, 2018.

  • Political Fact-Checking on Twitter: When Do Corrections Have an Effect?
    • Drew B. Margolin,
    • Aniko Hannak,
    • Ingmar Weber

    In the journal of Political Communication

  • Fair Sharing for Sharing Economy Platforms
    • Abhijnan Chakraborty,
    • Asia J. Biega,
    • Aniko Hannak,
    • Krishna P. Gummadi

    In Proceedings of the FATREC Workshop on Responsible Recommendation (colocated with RecSys 2017), Como, Italy, August 2017.

  • Why Do Men Get More Attention? Exploring Factors Behind Success in an Online Design Community
    • Johannes Wachs,
    • Aniko Hannak,
    • Andras Voros,
    • Balint Daroczy

    Proceedings of the 11th International AAAI Conference on Weblogs and Social Media (ICWSM'17) Montreal, May, 2017.

  • Bias in Online Freelance Marketplaces: Evidence from TaskRabbit and Fiverr
    • Aniko Hannak,
    • Claudia Wagner,
    • David Garcia,
    • Alan Mislove,
    • Markus Strohmaier,
    • Christo Wilson

    Proceedings of the 20th ACM Conference on Computer-Supported Cooperative Work and Social Computing (CSCW 2017), Portland, OR, February, 2017.

  • Location, Location, Location: The Impact of Geolocation on Web Search Personalization
    • Chloe Kliman-Silver,
    • Aniko Hannak,
    • David Lazer,
    • Christo Wilson,
    • Alan Mislove

    Proceedings of the 15th ACM Internet Measurement Conference (IMC'15), Tokyo, Japan, October 2015.

  • Measuring Price Discrimination and Steering on E-commerce Web Sites
    • Aniko Hannak,
    • Gary Soeller,
    • David Lazer,
    • Alan Mislove,
    • Christo Wilson

    Proceedings of the 14th ACM/USENIX Internet Measurement Conference (IMC'14), Vancouver, Canada, November 2014.

  • Get Back! You Don't Know Me Like That: The Social Mediation of Fact Checking Interventions in Twitter Conversations
    • Aniko Hannak,
    • Drew Margolin,
    • Brian Keegan,
    • and Ingmar Weber

    Proceedings of the 8th International AAAI Conference on Weblogs and Social Media (ICWSM'14), Ann Arbor, MI, June 2014

  • Measuring Personalization of Web Search
    • Aniko Hannak,
    • Piotr Sapiezynski,
    • Arash Molavi Kakhki,
    • Balachander Krishnamurthy,
    • David Lazer,
    • Alan Mislove,
    • Christo Wilson

    Proceedings of the 22nd International World Wide Web Conference (WWW'13), Rio de Janeiro, Brazil, May 2013.

  • Tweetin' in the Rain: Exploring societal-scale effects of weather on mood (Poster Paper)
    • Aniko Hannak,
    • Eric Anderson,
    • Lisa Feldman Barrett,
    • Sune Lehmann,
    • Alan Mislove, and Mirek Riedewald.

    Proceedings of the 6th International AAAI Conference on Weblogs and Social Media (ICWSM'12), Dublin, Ireland, June 2012.

Posters and presentations

  • Power of Digital Research Roundtable
    • Christian Sandvig
    • Aniko Hannak
    • Angela X Wu
    • Homero Gil de Zúñiga
    • Jean Burgess
    • Eszter Hargittai

    International Communication Association Conference, Fukuoka, Japan, 2016

  • Bias in Online Freelance Marketplaces
    • Aniko Hannak,
    • Claudia Wagner,
    • David Garcia,
    • Alan Mislove,
    • Markus Strohmaier,
    • Christo Wilson:

    In 2nd Annual International Conference on Computational Social Science, Evanston, IL, June, 2016.

  • Get Back! You Don't Know Me Like That: The Social Mediation of Fact Checking Interventions in Twitter Conversations
    • A. Hannak,
    • D. Margolin,
    • B. Keegan,
    • I. Weber

    Proceedings of the 8th International AAAI Conference on Weblogs and Social Media (ICWSM'14), Ann Arbor, MI, June 2014

  • Behavioral Responses to Fact-Checking Interventions in Online Social Networks
    • A. Hannak,
    • D. Margolin,
    • B. Keegan,
    • I. Weber

    Sunbelt 2014, St. Petersburg FL, Feb. 2014

  • Mitigating Sybil attacks on content rating systems
    • A. Molavi,
    • A. Hannak,
    • A. Mislove,
    • R. Sundaram
    SOSP 2011
  • Measuring and predicting sentiment on Twitter
    • A. Hannak,
    • E. Anderson,
    • L. Barrett,
    • S. Lehmann,
    • A. Mislove,
    • M. Riedewald

Press

Discrimination in Online Freelance Markets

Price Discrimination

Filter Bubble

Hungarian Press

Contact

Department of Informatics
University of Zurich
Binzmühlestrasse 14
8050 Zürich
Switzerland
+41 44 635 43 18

hannak@ifi.uzh.ch