1 ESEE 2011 - 9 th Conference of the European Society for Ecological Economics: Advancing Theory and Practice, Bogazici University, Istanbul, 13-17 June, 2011 A composite indicator on environmental sustainability performance at urban scale: the K8 approach Lorenzo Benini, Diego Marazza, Vittoria Bandini, Andrea Contin Environmental Management Research Group, Centro Interdipartimentale di Ricerca per le Scienze Ambientali (CIRSA) - Università degli studi di Bologna. Via Sant‟Alberto 163, 48100, Ravenna, Italy Corresponding: lorenzo.benini@unibo.it Abstract: In this paper we present the results of the KRUSKOT (K8) project, aimed at monitoring and communicating the environmental performances of the Faenza Municipality (Italy), through an environmental information platform. The environmental sustainability performance of the community of Faenza has been measured, on a monthly time step, through a composite indicator ranging from 1 (worst) to 10 (best). The monitored environmental themes are: water consumption, waste production and air quality. The current structure of the composite indicator, resulting from a major revision process, is presented and discussed. Particular attention is given to the aggregation method and its implication on the general meaning of the multi-dimensional measure and on the trade-offs among variables. 1. Introduction Even if many years have passed by from the World Summit on Sustainable Development of 1992, and its Agenda21 document, the need of knowledge on environment expressed by citizens and local communities is still growing. As several recent international initiative pointed out (e.g. the Beyond GDP conference held in 2007 by European Parliament, the Club of Rome, the WWF and the OECD; the Global Project on Measuring the Progress of Societies coordinated by OECD; the Stiglitz/Sen/Fitoussi report (2009) and, lastly, the communication of the European Commission on „GDP and beyond, measuring progress in a changing world‟ COM (2009) 433), new information is needed to measure the progress of societies which complement classical measure of progress. To achieve and maintain sustainability, and similarly, to measure the progress of society, policy-makers require timely information which demonstrates whether a system is generally becoming more or less sustainable and specific information on which parts need the most improvement (Mayer, 2008). In the context of policy analysis, indicators are useful in identifying trends and drawing attention to particular issues. Moreover, they are helpful in setting policy priorities and in benchmarking or monitoring performances (Nardo et al. 2008). In particular, composite indicators can contribute to