Research

• From model validation to policy resilience: stress testing healthcare systems with AI and cross-sectorial methodology [link]

with  Lieke Maas

We argue that health-economic models should be evaluated not only for their accuracy and cost-effectiveness, but also for whether the policies they support remain effective during real-world shocks. Drawing on stress-testing approaches from other disciplines, we explore how AI-driven scenario modelling can reveal vulnerabilities and trade-offs within complex healthcare systems. The editorial also addresses challenges concerning data quality, transparency, governance, and responsible implementation. Ultimately, we call for a shift from model validation towards policy resilience, supporting more robust, adaptive and patient-centred healthcare decisions.

• Tariefdifferentiatie bij afval huishoudens effectief maar doel nog niet gehaald [Dutch, link]

with Roselinde Kessels and Levi Kroezen

De Rijksoverheid stelt steeds strengere doelen voor het scheiden van huishoudelijk afval, maar de afvalscheiding is de afgelopen jaren gestagneerd. Een verdere landelijke uitrol van tariefdifferentiatie en minder vaak inzamelen kan de afvalscheiding verder doen toenemen.

In het kort: 

• Tariefdifferentiatie en een lagere inzamelfrequentie zijn effectief, maar niet alle gemeenten lijken dit te willen.

• Afvalscheiding is lager onder ouderen, laagopgeleiden en niet-westerse migranten.

• Communicatie en ondersteuning op basis van demografie kan de effectiviteit van tariefdifferentiatie mogelijk vergroten.

• On the Diameter of Arrangements of Topological Disks [arXiv]

with A. Abiad, B. Aronov, M. de Berg, J. Golak and A. Grigoriev

How many boundary crossings do you need to move between two points in a plane covered by overlapping geometric objects? We study this question for arrangements of topological disks, which may be non-convex and can intersect in multiple disconnected regions. We derive bounds on the number of disk boundaries that a curve connecting any two points must cross. These results establish bounds on the diameter of the dual graph of the arrangement and contribute to our understanding of the combinatorial structure of complex geometric systems.

• An Econometric Integration of Endogenous Patient Behaviors and Exogenous Market Shifts in Cost-Effectiveness Analyses

with L. Maas

Cost-effectiveness analyses often assume that drug prices and patient behaviour remain constant over time, even though pharmaceutical markets and treatment pathways are inherently dynamic. We develop a state-transition model that combines changes in drug prices—including price developments during market exclusivity and reductions following loss of exclusivity—with changes in patient behaviour, such as declining treatment adherence and toxicity-driven treatment switching. Across four illustrative treatment and disease settings, conventional static models produce substantially less favourable cost-effectiveness estimates. Our findings demonstrate the importance of incorporating both market and patient-level dynamics into health technology assessment.

• The Price of Periodicity on Inland Waterways [arXiv]

with J. Golak, A. Grigoriev and T. van der Zanden

Fixed operating schedules allow vessels to plan fuel-efficient journeys, but they can also create additional waiting time when arrivals are irregular. We quantify this “price of periodicity” and develop algorithms for constructing periodic schedules that minimize long-run average waiting time. The results support more predictable and potentially lower-emission inland waterway transport.

• Envy-free Pricing under Monotone Decay Valuations

with J. Golak and A. Grigoriev

How should seats be priced when customers value them according to their location and will always choose the seat offering them the greatest utility? We model this as a geometric envy-free pricing problem and study both continuous seating spaces and discrete tessellations. We develop exact and approximation algorithms for maximizing revenue while ensuring that customers have no incentive to switch seats.

• A systematic review and meta-analysis: the effect of excessive weight on productivity [PROSPERO]

Pawel Lubelski, L Maas, Mickael Hiligsmann, Alexander Grigoriev, Freija van Lent, G. Ardine de Wit, Marije Oosterhoff

Excessive weight may affect productivity through labour-market participation, absenteeism, reduced functioning at work and school attendance. In this systematic review and meta-analysis, we synthesize the available evidence on the relationship between measures of excessive weight —including body mass index, waist circumference, and waist-to-hip ratio— and productivity outcomes. By combining evidence across different populations and research settings, the study aims to clarify the economic consequences of overweight and obesity and to identify important gaps in the existing literature.

• A multi-level model for value chains of smallholder farmer commodities 

with A. Grigoriev and in collaboration with the Fair and Smart Data research institute

Consumers often pay a premium for sustainably produced commodities such as coffee and cocoa, but only a limited share of this premium may reach smallholder farmers. We develop a multi-level model that captures the interconnected decisions of consumers, producers, supply-chain actors and regulators. The model allows us to study how purchasing behaviour, production decisions, market structures and regulation jointly determine the distribution of value along the supply chain. Our aim is to evaluate policies and market arrangements that could help farmers earn a living income.

• Interdisciplinary SBE PhD funding, with Lissa Melis and Tjark Vredeveld (€200.000)

• Research Fellowship, with Alex Grigoriev, Fair and Smart Data Institute (€15.000)

• Travel Grant, Maastricht University (€3.000)

• 2025 - Present: European Women in Mathematics – The Netherlands: Maastricht University representative

• 2024 - Present: Management Team member for the Data Analytics and Digitalization department

• 2024 - Present: Education Coordinator for the Data Analytics and Digitalization department

• 2020 - 2024: Organization of PhD Brownbag seminar, an open seminar series at Maastricht University in which PhDs can practice their presentations and improve their presentation skills, while getting feedback on their research approach.

• 2021 - 2023: Data Analytics and Digitalization representative for the Maastricht University School of Business and Economics' PhD Committee

• 2022-2023: Reviewer for the School of Business and Economics' International Classroom Committee 2023

• Fair Trade Premiums: How Much Reaches the Farmers? [Blog]