My research focuses on the patterns that structure conflict and cooperation between political actors. This can be an ideological structure, such as a political space, but also the division between coalition and opposition. My research has examined four areas where this is of particular importance:

  1. the ideological lines of conflict between parties;
  2. parliamentary behaviour;
  3. new parties
  4. and interest groups, in particular the relationship between parties and interest groups.

For the documentation centre, I also examine developments in European and Dutch party politics.

Ideological lines of conflict
A central question in my research is which lines of conflict structure political decision-making and voting behaviour: does the left-right dimension suffice? Or has a new political space developed because of globalization, EU integration and immigration? I examine these developments at the level of the voter and the party, both for national party systems and the EU party system. In this context, I lead a research project about the economic positions of radical right-wing populist parties.

Parliamentary behaviour
A second, related, field of interest, is parliamentary behaviour. In addition to ideological lines of conflict, specialisation and the division between coalition and opposition structure MP behaviour. The last has gained a new meaning since the Netherlands has been governed by a number of minority governments. I In order to map behaviour in the Dutch parliament I have collected all votes in the Dutch parliament since 1945 together with T. Louwerse and C. van Vonno (in the Dutch Parliamentary Votes Data Base), but also parliamentary questions, motions, amendments and legislative initiatives. We are in the process of coding these documents and election manifestos into the Comparative Agendas Project coding scheme.

New parties
New parties develop on new lines of conflict. In my PhD-research I have examined to what extent new political parties are able to create new lines of conflict at the political level. Together with a number of colleagues I have studied to what extent new parties really form on new untapped issues.

Interest groups
The relationship between political parties and interest groups can be structured by ideological divisions as well as other divisions, such as the division between coalition and opposition. This is one of the issues I examine, for instance as Dutch contributor for the Left-wing Parties and Trade Unions project. Between 2011 and 2012 I worked for INTEREURO, a project about the role of interest groups in the EU.

Dutch and European parties
For my position at DNPP I examine the development of Dutch and European parties. Part of the work is descriptive historical research into the most important events in Dutch politics and Dutch political parties for the Political Data Yearbook. Additionally, I study the development of European political parties ('parties at the European level'), in particular the European People's Party and the Alliance of Liberals and Democrats in Europe and the role that national parties play in this form of party-political European integration.

Research interests
Comparative politics, political parties, party systems, party positions, parliamentary behaviour, interest groups, voting behaviour and political science methodology.

Methodological specialization
Scaling methods, textual analysis, parliamentary voting analysis.