Abstract: Decision making is based on the analysis of information obtained from different sources.Statistical data,measured data and mathematical models are used for scientific analyses. But data have deviations and mathematical models are only the approximations of the real world, thus the information from them are incomplete. The accumulated experience/knowledge of experts are usually qualitative, imprecise or flexible,but they also reflect the objeective world to a certain degree. This paper discusses the possible methods of introducing the experience/knowledge into decision making.