Modeling for litigation: mixing qualitative and quantitative approaches

A contractor to the channel tunnel project instigated litigation to claim for the costs of disruption and delay. We used several interacting models to make the case for the claim more persuasive, coherent, and verifiable. Mixing qualitative modeling (large cognitive maps) with influence models and with system dynamics simulation modeling improved the quality of the claim. Quality, in this case, being that the modeling process was understandable to the client to the extent that it could argue the claim in court, that every aspect was expected to be transparent to the judge, and that it was robust and defensible management science. Cycling between modeling approaches gave benefits that could not have been attained by either hard or soft modeling in isolation. The claim ultimately was settled satisfactorily out of court with the client acknowledging that the modeling played a significant role.