Forthcoming PhD defences

More information will be published soon.

Past PhD defences 2024

25 January 2024 - Sam van der Vlugt

Sam van der Vlugt

  • Thursday 25 January 2024 - 2:30 pm at Università di Salerno, Italy (It was also possible to attende the defense online).
  • Supervisors: prof. dr. Bruno Peeters (University of Antwerp) & prof. dr. Pasquale Pistone (Università di Salerno)
  • Joint PhD Università di Salerno, Italy & University of Antwerp, Belgium
  • Title: Rethinking Tax Sovereignty in the European Union: Towards Principled European Tax Integration


This dissertation deals with the interaction of national taxing powers and the body of European Union law. The dissertation takes a constitutional angle by firstly tracing the roots of the current division of public power and the exercise of sovereignty by the state throughout history up to the current day conception that should be taken of sovereignty. This conception is subsequently applied to the integration in taxation in the European Union, Herein, several problems are identified for the field of tax law that are hampering the fulfilment of the democratic promise of the project of European integration as enclosed in the Treaties of the Union. To address these difficulties with respect for the distinct features present in the national setting, the analysis sketches a dialogical sphere that is already present in the Treaties that could resolve this integrative deadlock, and proposes a new integrative path for especially direct taxation that answers to the goals that are laid down in the Treaties. This will require a significant redevelopment of the integrative agenda that is currently tabled by the Commission, and especially that the Member States take up their democratic responsibility. If not, the constitutional framework that is present in both the national and the supranational setting might provide the next obstacle to the current common exercise of taxing powers, as this is not done in line with the goals of the Treaties and thus the democratic promise these contain towards citizens.

Past PhD defences 2023

15 November 2023 - Wouter Dister

Wouter Dister

  • Wednesday 15 November 2023 - 5.00 p.m.
  • Supervisors: prof. dr. Anne Van de Vijver (University of Antwerp) & prof. dr. Miet Vanderhallen (University of Antwerp and Maastricht University)
  • Title: The Belgian Co-operative Tax Compliance Pilot ProjectKey Succes Indicators
  • Abstract

8 September 2023 - Dieter Brughmans

Dieter Brughmans

  • Friday 8 September 2023 4.00 p.m.
  • Supervisors: David Martens & Bruno Peeters
  • Title: Counterfactual explanations for real-world applications


We first introduce NICE, a novel algorithm for tabular data that specifically takes into account algorithmic requirements that are often overlooked. NICE exploits information from the training data to speed up the search process of finding an explanation. Our extensive benchmarking study indicates that NICE’s explanations have desirable properties compared to the current state-of-the-art. Next, we study the implementation of NICE within the risk management system at the Belgian Customs Agency. Our research identified four stakeholders: data scientists, targeting officers, domain experts, and decision subjects. For each of the stakeholders, we investigate how they can benefit from local explanationmethods and what their requirements are regarding the form of these explanations. Broadening the scope of our research beyond tabular data, we introduce SEDC and SEDC-T, two counterfactual algorithms for image classification. We experiment with various segmentation methods to find meaningful counterfactual explanations. Finally, this work tackles the ethical issue of disagreement among counterfactual explanations, revealing how their diversity can potentially be exploited to fairwash ML models by hiding sensitive features. Our study finds alarmingly high disagreement levels between the tested methods.

11 September 2023 - Pedro Moraya Barros

Pedro Moraya Barros

  • Monday 11 September 2023
  • Supervisors: Ann Jorissen & Anne Van de Vijver
  • Title: International Personal Taxation and Country Characteristics


The increase in capital mobility in the last couple of decades, along with the rise in popularity of offshore investments, tax havens, and foreign taxation strategies, gave prominence to the importance of international taxation in domestic politics. Although income taxation often represents more than half of states’ revenue and has been positively correlated with economic development, 51 fiscally sovereign jurisdictions (which represent about 25% of the countries, 15% of the FDI, and 5% of the GDP of the world) chose to not tax their residents in foreign and/or domestic source income. The large divergence between personal income tax systems that exist today leads significant amounts of capital to flow from high to low tax jurisdictions, while potentially increasing wealth inequality. Thus, what are the country's characteristics related to the choice of personal income tax and related policies? To contribute to the answer to this question, I develop a 3-article dissertation divided between: (Chapter 2) What are the characteristics related to a country (not) having personal income taxation? (Chapter 3) What are the characteristics related to a country taxing residents on domestic-source income and not on foreign-source (i.e. personal territorial taxation)? (Chapter 4) What are the characteristics related to a country having policies potentially used by individuals to avoid or evade tax duties, i.e. the official selling of passports and visas? To test the theoretical models underlining these relationships based on Institutional Theory, Median Voter Theorem, Modernization Theory, and Bellicist Theories, I created several novel datasets that cover all sovereign jurisdictions in the world often through a long time series. Using these datasets, I employ a series of quantitative methods (e.g. ordinary least squares, maximum likelihood estimations, event analysis, error correction models, and instrumental variable approaches) that find significant empirical results for the fields of personal taxation, institutions, and foreign investment. This dissertation also has implications for broader questions in the literature.