Wiley Handbook of Science and Technology for Homeland Security, 4 Volume Set

SCENARIO ANALYSIS, COGNITIVE MAPS, AND CONCEPT MAPS

KENNETH G. CROWTHER AND YACOV HAIMES

Center for Risk Management of Engineering Systems, Department of Systems and Information Engineering, University of Virginia, Charlottesville, Virginia

1 INTRODUCTION

In her book Pearl Harbor: Warning and Decision [1962] recently cited by the 9/11 Commission Report [1], Roberta Wohlstetter made the following comment [2]:

It is much easier after the event to sort the relevant from the irrelevant signals. After the event, of course, a signal is always crystal clear; we can now see what disaster it was signaling since the disaster has occurred. But before the event it is obscure and pregnant with conflicting meetings.

Those same words, which describe the Japanese attack on Pearl Harbor in 1941, could be used 60 years later to describe many modern disasters. Nassim Taleb [3], in his highly provocative essay The Black Swan: The Impact of the Highly Improbable, confirms Roberta Wohlstetter's insight with one additional caveat—the hindsight understanding produced by assessing signals after an event is usually not general enough to yield insight, missing causal understanding, and often lacks meaningful impact on decisions. “Clear” hindsight without inventive foresight is insufficient to cope with risks of improbable and elusive events to the homeland. Moreover, it is the improbable, elusive events that result in the greatest impact (e.g. unimagined terrorist attacks with passenger planes in New York; ...