During the last years much of his work has focused on the theory and practice of environmental policy evaluation. Based on his research he has published several monographs and numerous articles in academic journals. He was one of the two editors of the issue "Environmental Program and Policy Evaluation: Addressing Methodological Challenges" of the journal New Directions for Evaluation that is published in June 2009. Recently the focus of his work has shifted to energy and climate policy issues. In 2008 he was leading a team, which made the study “Mainstreaming and Coherence of Climate Policies” for the Finnish Prime Minister’s office. He was also leader of the European research team that wrote the report “Climate Policy Integration, Coherence and Governance” which was published by the Partnership for European Environmental Research in March 2009. In the near future his research will largely be related to environmental governance in general and climate governance in particular. Environmental governance combines the general transition of public policies towards less hierarchical and more network based approaches, the reduced scope of action for the national state as well as the special features of environmental problems. Environmental problems are complex and conflicting. They contain a lot of uncertainty and to get to grip with causes and effects is often challenging. In addition the impacts of policies will often be seen only after years, sometimes even decades. These features make governance and especially multi-level governance challenging. 

Some years ago the focus of his research shifted to energy and climate policy issues. In particular to issues related to stability and change in energy systems and the role of innovation and climate policies for these processes. Since the end of the 1990s much of his work has focused on the theory and practice of environmental policy evaluation and the role of policy evaluation in reflexive governance.