A new paper written by Andrew Farmer, Patrick ten Brink and Marianne Kettunen examines the role of impact assessments in the implementation of EU environmental law by the Member States. EU environmental law can allow flexibility in the way that it is implemented by Member States. It can, for example, set an overall environmental objective for which Member States are free to adopt any instrument necessary to reach this target. As a result, Member States can adopt measures which vary in their efficiency (such as costs to businesses), which could reflect national legal constraints, pre-existing practices, etc. In order to assess which instruments to use, Member States should undertake some form of impact assessment, analysing the costs and benefits of different options. The recently released paper by IEEP staff examines these issues. It is published in the Journal for European Environmental and Planning Law. Vol. 3, pp 395-405.