Examination of Decision Support Systems for Composite CBA and MCDA Assessments of Transport Infrastructure Projects

This paper examines decision support systems (DSS) for composite appraisals of transport infrastructure projects comprising both cost-benefit analysis (CBA) and multi-criteria decision analysis (MCDA). Two DSS, REMBRANDT and COSIMA, are in this context examined and compared using a case study dealing with alternatives for a new high-speed railway line in Sweden. The REMBRANDT system is based on multiplicative value functions and makes use of pair wise comparisons on both attribute and criteria level. The COSIMA system is based on additive value functions and makes use of the REMBRANDT technique using pair wise comparisons on attribute level and swing weights on criteria level. One difference between the two approaches is the focus the COSIMA system puts on combining the CBA and MCDA results influencing, among other things, the way that the final results are expressed. Finally, a recommendation for the use of DSS within transport infrastructure appraisals is set out.