i am interested in making digital power visible to the public and guiding the development of accountable, sustainable, and safe algorithms that better serve the public interest.

my group and i study what happens when complex or opaque algorithms are used to share sensitive data, to make important determinations in the public eye, and to shape our interactions with online platforms. our work shows that understanding the impact of data and algorithms is difficult and requires a human-centred approach.

my research shows that interactions betweens humans and algorithms can lead to unintended consequences, often difficult to anticipate. for example, our work showed that supposedly "anonymous" datasets can often be re-identified with surprising ease, challenging common assumptions about privacy. Nature Communications, 2019 our research revealed how pricing algorithms in online markets can inadvertently lead to collusive behavior, affecting the prices consumers pay. Nature Machine Intelligence, 2023 our work also shows how interactions between humans and AI systems, such as language models, can lead to unintended harms from reinforcing prejudices to manipulating user behaviours.

i am interested in building empirical tools and methods to help people better understand the technology they interact with. i lead the Observatory of Anonymity, an interactive website in 89 countries where visitors can find out what makes them more vulnerable to re-identification and where researchers can test the anonymity of their research data.

visit my Google Scholar profile for an up-to-date list of my publications

prior to joining Oxford, i received a PhD from the Université catholique de Louvain and worked as a researcher at the Data Science Institute and Computational Privacy Group of Imperial College London, at the ENS de Lyon, and at the MIT Media Lab.

my work has been published in peer-reviewed journals and conferences (Nature Communications, Science Advances, Nature Machine Intelligence, CHI, FAccT, Usenix Security) and has been covered by 160+ newspapers (New York Times, The Guardian, The Telegraph, Forbes, El Pais, Scientific American) as well as featured in John Oliver's Last Week Tonight, BBC World Service, France TV, and Radio Canada. my research on the limitation of anonymisation practices has been referenced by the European Commission, OECD, World Bank, WEF, FTC, by European data protection authorities, in US legal changes to the UK's Data Protection Bill.

i was General Chair of Hot Topics in Privacy Enhancing Technologies (HotPETS) in 2023 and 2024, and have been Area Chair for the ACM FAccT Conference on Fairness, Accountability and Transparency 2024 and 2025. i sit on a range of programme committees and have reviewed from numerous journals, from Nature to Big Data & Society, as well as international funders.

at OII, i taught in the MSc in Social Science of the Internet and the MSc in Social Data Science. i also served as programme director for the DPhil (PhD) in Social Data Science in 2023 and 2024.

Fairness, Accountability, and Transparency in Machine Learning (2022–2024). with Ana Valdivia, we introduced how ML technologies can bring social progress but reinforce oppression and reproduce social injustice, equiping social science students with technical tools to engage critically with automated decision making, data mining, and digital technologies.

Accessing Research Data on the Social Web (2022). Computational Methods for the Social Sciences (2023). with Fabian Stefany, we developed students' Python programming skills to study online culture, communities, and human behaviours, by collecting and wrangling data from social websites and platforms.

i have advised interns, undergraduate and master's students, doctoral students, and postdoctoral researchers at Oxford, Imperial College London, UCLouvain, and MIT. visit my research group page for a list of current and past members.

you can contact me by email at X@Y where X=luc.rocher and Y=oii.ox.ac.uk. i receive a very large number of emails every day, and at times cannot answer them all. if you are a student, there are excellent guides online on writing effective emails.

follow me on Mastodon @cynddl@mamot.fr Bluesky @rocher.lc LinkedIn for occasional research updates.

i am available for quotes, interviews, and public speaking. if you are a journalist, email is the best way to reach me.

i enjoy playing clarinet and melodeon, sewing clothes, and building bicycles that i take them on long adventures. in past lives, i was a wikimedia administrator; i was also a photographer with a few exhibitions across Europe.