Designing fairer and more efficient decisions with maths

How can we make decisions that are both fair and efficient when everyone is pursuing their own interests? Sophie Klumper explored this question during her PhD research at CWI.

On 23 October, the CWI PhD student successfully defended her thesis at the University of Amsterdam, entitled The Gap and the Gain: Improving the Approximate Mechanism Design Frontier in Constrained Environments’. Her results provide new mathematical tools for improving strategic decision-making in areas such as public resource allocation, auctions, and online markets.

Fair and efficient

Many real-world decisions depend on honest sharing of information by people, companies or algorithms. Mechanism design studies how to build rules that make such honesty the best strategy. In her PhD research, Klumper focused on situations where decisions must also respect strict limits, such as a fixed budget or limited capacity. She developed algorithms that remain both fair and efficient under these constraints, ensuring that participants act truthfully while the overall outcome still serves the common good.

Group picture of the CWI PhD defence of Sophie Klumper (N&O), 23 October 2025, at the UvA. Own picture.
CWI PhD defence of Sophie Klumper (N&O), 23 October 2025, at the UvA. Own picture.

Game theory

Sophie Klumper did her PhD research in CWI’s Networks and Optimization group, supervised by Guido Schaefer and Rob van der Mei. Her thesis advances the theory of mechanism design and contributes to a better understanding of efficiency losses caused by strategic behaviour - a key concern in game theory. The work connects abstract mathematical models with practical decision problems, from facility location planning to online advertising markets.

This PhD research was supported by the NWO Open Technology Programme.

More information

Header picture of an online auction: Shutterstock.