1 Complexity in decision-making: the case of Maasvlakte II Connecting decisions, arenas and actors in spatial decision-making Marcel van Gils, Erik-Hans Klijn Paper for the 45 th Congress of the European Regional Science Association "Land Use and Water Management in a Sustainable Network Society" Vrije Universiteit Amsterdam 23-27 August 2005 Abstract: Decision-making about spatial projects is very complex. Decisions to develop the Rotterdam harbour are being taken in a network of local, regional, national, European and international actors, both public and private. These decision-making processes show a lot of complexity and the outcomes are of great importance for the development of the harbour. The complexity results from interactions between actors connected in different arenas all thinking about the same project. In this paper we use network theory and especially the concepts actors and arenas to highlight the complexity of decisions and the connections between various separate decisions. We also show the outcomes of the decision making process are a result of the various connections that are being made. The spatial project at the core of the paper is a harbour expansion project called Maasvlakte II. Key words: complexity, Maasvlakte II, actors, arenas, interactions, Drs. Marcel van Gils Dr. Erik-Hans Klijn Erasmus University Rotterdam Erasmus University Rotterdam Centre for Public Management Centre for Pubic Management Room M8-13 Room M8-30 P.O. Box 1738 P.O.Box 1738 3000 DR Rotterdam 3000 DR Rotterdam E-mail: vangils@fsw.eur.nl E-mail: Klijn@fsw.eur.nl