Scenario building is an analytical method to make forecasts. Alternative scenarios of the future can be described as well as the different ways that lead to these scenarios. You can differ best case, worst case and trend scenarios. Scenarios illustrate possible futures in connection with causal processes with the aim of sensitising for possible future events. In Contrast to forecasts or predictions, scenarios allow uncertainties and should be seen as an estimation for future developments in preparation for decision-making, which supports strategic planning considerations. 
 Postma, T., Liebl, F. (2005): How to improve scenario analysis as a strategic management tool? Technological Forecasting & Social Change 72 (2), 161-173.
 Bood, R., Postma, T. (1997): Strategic learning with scenarios, European Management Journal, 15 (6), 633-647.