In 2008 a work started on developing a method for cost-benefit-analysing investment proposals in defence studies. The emphasis was on developing a checklist for identifying cost drivers. In 2009 this work was extended to identifying and estimating cost drivers for certain alternatives and that in connection with the defence study "ISTAR i Luftarenan, LUFT 070801S" (Intelligence, Surveillance, Target Acquisition and Reconnaissance). During the progress of work the importance of estimating "benefit" - and hence scenarios - became clear. Since the conditions were missing for evaluating the benefits of the different alternatives, their main characteristics were highlighted. Performance, development potential, and tactical impact were described as counterweight to cost analysis.