With its study ‘Economically Optimal Water Safety in the IJsselmeer Region’ the Netherlands Bureau for Economic Policy Analysis (CPB) has made a major step forward in research into water safety. This is an impressive study that brings together a vast amount of hydrological and economic knowledge superbly. In particular, taking dependencies into account in the probability of dyke flooding is an important innovation. The model that has been developed, Diqe-opt, is an innovative and very useful tool. Generally speaking, the right research questions have been posed and appropriate methods and the best possible data have been used.

These are the conclusions of a committee of economic experts in a second opinion. The committee also supervised the study while it was in progress. It was chaired by SEO Research Director Prof. Carl Koopmans, and the members were Prof. Ekko van Ierland (Wageningen University), Prof. Piet Rietveld (VU University) and Prof. Anne van der Veen (University of Twente).