Political scientists Tom Louwerse, Simon Otjes & Cynthia van Vonno introduce the Dutch Parliamentary Behaviour Dataset, a record of parliamentary (voting) behaviour in the Dutch Tweede Kamer (Second Chamber, House of Representatives) since 1945.

The authors explore the decision-making processes and debates surrounding EU member states' troop contributions to CSDP military deployments.

How many written parliamentary questions does each party put to each minister? Political scientists Simon Otjes (University of Groningen) and Tom Louwerse (Leiden University) studied the practice in Dutch parliament and found that parties use parliamentary questions strategically as part of their ‘permanent…

Beyond the immediately visible plenum, parliaments are highly complex institutions. They work through various venues in which decisions are prepared or even taken. The two main institutions in this regard are parliamentary party groups, which comprise legislators who are elected under the same party…

The 2025 Dutch Parliamentary Study is a comprehensive survey of views and experiences of members of the Senate and House of Representatives. This survey, conducted by Leiden University’s Institute of Political Science, is part of a long and rich tradition of parliamentary surveys in the Netherlands.…

Akbik and Diessner expand the classic typology of police-patrol and fire-alarm oversight with two new categories: planning bureaus and ambulance chasers.

How can teachers be motivated by their students’ data in making stepwise changes to their teaching practices?

How do individuals make decisions? What determines the quality of group decisions? When and why do people cooperate with others? How does intergroup competition evolve?

In science, it is of vital importance that multiple studies corroborate the same result. Researchers therefore need to know all the details of previous experiments in order to implement the procedures as exactly as possible. However, this is becoming a major problem in neuroscience, as animal studies…

Simona Demková, Assistant professor at the Europa Institute of Leiden University, publishes her book ‘Automated Decision-Making and Effective Remedies: The New Dynamics in the Protection of EU Fundamental Rights in the Area of Freedom, Security and Justice’.

Research in Leiden University’s Institute of Political Science focuses on the dynamics and the interaction of political institutions, individual decision-making, and collective behaviour.

This minor focuses on how our thoughts, emotions and behaviour are influenced by other people, and how we influence other people.

Efficiently responding to others’ emotions has great survival value, especially for social species, such as primates, who establish close, long-term bonds with group members. The closest living relatives to humans are the chimpanzee and the bonobo. Studying these species, and comparing them on the exact…

This article explores the concept of issue prioritisation within the context of public administration research, focusing on decision-making processes.

Our project focuses on the analysis of decision-making processes in the European Union (EU) and explores how approaches and tools to understand decision-making found in both the Natural and the Social Sciences can be linked, knowledge between these traditions exchanged and synergies utilized. To explore…

PACES is an innovative, inter-disciplinary and multi-level research project that asks, How do changes in society, individual life experiences and migration policy shape decisions to stay or to migrate over time and across countries? And how can this knowledge inform future migration policies and gov…

What political factors affect the speed or duration of EU legislative decision-making?

This thesis examines the complexity of legislative decisions within the EU, with a specific focus on the Council of the EU.

The starting point for this research project is the notion that the human brain is susceptible to all kinds of fallacies and biases that affect our perceptions and influence our reasoning outside of our conscious awareness. Indeed, most people think they are merely observing facts and that they process…

Studies of perceptual decision-making typically present the same stimulus repeatedly over the course of an experimental session but ignore the order of these observations, assuming unrealistic stability of decision strategies over trials. However, even ‘stable,’ ‘steady-state,’ or ‘expert’ decision-making…

We present an extensive study of methods for exactly solving stochastic constraint (optimisation) problems (SCPs) in network analysis. These problems are prevalent in science, governance and industry.

As a research project between four Jean Monnet Chairs - two located in Europe, one in Canada and one in the U.S. -- the project DEUBAL has been approved in 2010 for co-financing by the European Commission. DEUBAL aims to study changes in European decision-making due to the Lisbon Treaty, by a combination…

How do processes of coalition-formation influence patterns of decision-making in the European Union?

MPs in the Netherlands are first and foremost motivated by their direct environment, i.e. the parliamentary and partisan institutions.

The focus of the Multicriteria Optimization and Decision Analysis (MODA) group is to develop foundations of methods in multi-objective optimization.

How do cognitive, motivational, and affective processes interact to select actions?

How do parliamentarians secure their political future? Are their activities in the legislature connected to their place on the candidate list from one election to the next? Political scientists Tom Louwerse and Cynthia van Vonno examine the Dutch case. Their main finding is that speaking in the plenary…

PhD defence

Big data promises to transform public decision-making for the better by making it more responsive to actual needs and policy effects. However, much recent work on big data in public decision-making assumes a rational view of decision-making, which has been much criticized in the public administration…

Nadine Raaphorst wrote an chapter for The Oxford Handbook of Administrative Justice about how two notions of fairness are studied in street-level bureaucracy literature and about the factors that influence how bureaucrats behave in this regard.

Cynthia van Vonno, political scientist at Leiden University, explains why individual MPs vote according to the party group line.