Abstract: Only few areas where humans not have to estimate the development of economy, environment or society prior taking a decision. But how? Guessing? Trust your snap decisions? Rely on expert's knowledge? Or with the help of a computer model? What follows is a short comparison of these options and a presentation of a new possibility of computer-aided modeling. The result: Guessing, your snap decision and expert's knowledge can be combined and extended in easy to build qualitative models.