I am an Associate Professor in Political Science at Leiden University, the Netherlands. I am currently Director of Research at the Institute of Political Science.

My research and teaching concern elections, political representation and parliamentary politics in the Netherlands and other established democracies. My main research project, Who opposes?, focuses on government-opposition cooperation in parliament and is supported by a Vidi grant from the Dutch Research Council (NWO). I am co-author of Governance and Politics of the Netherlands and co-editor of the Oxford Handbook of Dutch Politics.

I created and maintain the polling aggregation project Peilingwijzer, blog about my work and regularly appear in news media.