principle no technological progress during the transition period is anticipated. This is measured afterwards on the basis of the development of the distance (écart) between the SNI and the NI in the course of time. Estimates The work on the estimate of an SNI started in the mid-1960s. The first rough estimate of an ‘SNI’ for the world by Jan Tinbergen and Roefie Hueting in 1991 arrived at 50 percent of the world production level: the sustainable world income. A much more advanced estimate for The Netherlands was made in 2001 by a collaboration of the National Institute for Public Health and Environment (RIVM), Statistics Netherlands (CBS) and the Institute for Environmental Studies (IVM). The estimate arrived at around 50 percent of the production level, c.q. the national income of The Netherlands. This corresponds with the production level of the beginning of the 1970s. As the population was smaller at that time, the consumption per person was substantially higher than 50 percent of the present level. In accordance with the principles of the SNI it is assumed that all countries in the world simultaneously switch over to environmental sustainability and that the costs thereof are comparable with those of The Netherlands. In the period 1990-2000 the distance between de NI and SNI increased with approximately 10 billion euros. Reviews Neoclassical economics finds opposition from ecological economics, while that opposition would be less needed due to Hueting's more neoclassical analysis of the environment. The neoclassical SNI has different results than e.g. Robert Costanza et al. (1997). A critical review of the method used by Robert Costanza et al. (1997) is given by Roefie Hueting et al. (1998). References Further reading B. de Boer and R. Hueting (2004), Sustainable national income and multiple indicators for sustainable development in: OECD, Measuring sustainable development, p 39-52 Th. Cool, (2001), Roefie Hueting and the SNI (in Dutch), ESB 4321, p 652-653. O. Kuik (2006), Sustainable national income (SNI). This paper has been written for the Overview of Advanced Tools for Sustainability Assessment of the “Sustainability A-Test” project of the European Union, DG Research, see http://ivm5.ivm.vu.nl/sat/?chap=14 R. Hueting, (1974), New scarcity and economic growth, Dutch ed, Agon Elsevier, Amsterdam, Brussel, English ed, North-Holland Publishing Company, Amsterdam, New York, 1980 R. Hueting, (1996), Three persistent myths in the environmental debate, Ecological Economics, 18 (2), p 81-88. Also published in: E.C. van Ierland, J. van der Straaten, H.R.J.