In research, we analysed the way cost-benefit analyses (CBA) were carried out in governmental and selfgovernmental projects which were partly financed by the European Union. The primary aim was to establish
how the way these CBAs are carried out can be improved in the case of these institutions. By taking account
of the environmental endowments and social factors, it became obvious that the quantity and presence of
externalities is usually more significant than in the case of the assessment of economic factors. The presence
of quantified benefits in the development documents could make it much easier for the decision makers to
decide whether the investment possesses suitable characteristics in an economical, environmental and social
sense too, in the case of projects and development concepts, or not. Therefore, its realization will certainly modify the welfare curve in a positive direction. In spite of this it can be stated that the incorrect methodical approach of the economic factors result many extern effects in the evaluation, which place the certain development programmes in the centre of the preferred economic decisions in a way that they cause many
social and environmental damages