Social indicators are a varied set of measures to describe and evaluate social trends in society. In th i s chapter, origins, different approaches, and leading research projects in the "social indicator movement" are d iscussed. Some examples of Dutch social reporting are also presented. Further­ more, the social indicator movement is con­ fronted, for theoretical and methodological reasons, with a split between objective and subjec­ tive social indicators. As examples, the main research projects of the Organization for Econ­ omic Co-operation and Development (OECD) in Paris and the Institute for Social Research ( ISR) in M ichigan are outlined. Some questions about the macro-and micro-approaches, and especially about the harmonization of"social indicators", are discussed to indicate the social indicator perspective.