-> Increased investment in measures for security improvements often has far-reaching societal impacts. -> The DESSI-system offers support in the decision making process concerning security invest- ments. -> A web-tool guides you through the process and visualizes the results. -> The participation of as many diverse stakeholders as possible supports the multi-dimensional analyses of different technical and organisational alternatives of security investments. -> Through its seven impact dimensions DESSI offers a holistic overview of the consequences of investment alternatives.