Written by the PIARC Economic and Finance Committee, the paper is concerned with public improvements and the relevant methods of investment appraisal. The aim is not to set down a rigorous appraisal methodology but to provide guidance to enable each decision maker to adopt appropriate methods within the context of the individual problem faced.

The first chapter establishes the general context of decision making. The following two chapters describe the two main types of method available; single criterion analysis and multi-criteria analysis. It is then demonstrated that the choice of method is dependent upon the nature of the problem posed and the level of decision in question. A final chapter explains the methods used in various countries (France, Morocco, United-Kingdom, Hungary and Belgium) and by the World Bank.