Decision support, especially the use of decision support systems, for IT-decisions is a widely treated subject in IS literature. However, only few studies seem to have targeted success factors, which lead to effectiveness and efficiency of and also to satisfaction with IT-decision processes in a holistic view. The focus of the book is on antecedents as well as inhibitors that have an impact on perceived satisfaction of decision making processes. The paper examines the influence of constructs such as IT- support, decision support framework adoption, decision support method adoption, management support and legislative regulation on the dependent construct using a structural equation modelling (SEM) approach. A second important aspect considered by the research instrument is the diffusion of decision support methods in Austrian companies for IT-transformation and -innovation decisions. The rich treatment in academic literature is by far not reflected by the actual use of methods in practice. The book concludes guidelines for management to improve their decision support processes for IT- decisions.