Abstract
Large projects in natural settings, such as hydropower and road developments, can be controversial because of conflicts with tourist and recreation interests. Predictions can be very different from ex post realities, indicating low quality of impact assessments. This paper presents basic concepts, theories and realities in a longitudinal case study, which has audited the effects on tourism and recreation from major projects in Norway. Among the effects identified are changes in latent and effective demand, displacement and substitution, but interaction and cumulative effects have also been import-ant. One way of improving ex ante predictions is, therefore, a dynamic step-wise approach to impact assessment.