The present field study will get an answer to the question, which influence has the experience on the risk aversion of decision maker. How and to which extent a risk-averse decision maker will use his experience to make a decision influences the decision result. Therefore examines the study the influence of experience on the decision-making behaviour of decision makers in the management of small and medium-sized enterprises (SMEs) by complex and risk-encumbered investment decisions. The study can be shown, that decision makers use different forms of experiences and that increasing experience influences the risk aversion of the decision makers. It can be also shown, that chances and risks of a decision are evaluated independently by decision makers. The study shows also the relationship between subjective experience and risk aversion. To improve the quality of risk assessment, it will be propose to use a combination of methods for a more objective risk assessment.