Sustainability as defined by the Brundtland Commission, is a composite and thus ambitious policy target. It comprises environmental, economic, social, and institutional criteria with equal importance. Because of this complexity the first step of a (Local) Agenda 21 process should be to develop a Vision of a sustainable society-a "leitbild"-useful as a compass, not a road map (or, even worse, a blueprint), attached by indicators that help to measure progress, distance to target, and failures of plans or their implementations. In the following article a model is proposed how local sustainability indicators can be developed and how they can help to reduce the complexity of sustainability and to concretize a program for the Local Agenda 21. To get a practical impression of the theoretical presentation an example is given in the last part of the article. It shows the experiences made while developing sustainability indicators in the City of Iserlohn. (C) 2000 Elsevier Science Inc. All rights reserved.
