Counterfactual reasoning evaluates conditional claims about alternate possibilities and their consequences (i.e., "What If" statements). Counterfactuals are essential to intelligence analysis. The process of counterfactual reasoning has three stages. First, one must establish the particular way in which the alternate possibility comes to be (i.e., develop its "back-story"). Second, one must evaluate the events that occur between the time of the alternate possibility and the time for which one is considering its consequences. And third, one must examine the possible consequences of the alternate possibility's back-story and the events that follow it. In doing so, an analyst must connect conclusions to specific types of strategic assessment: decision making under risk or decision making under uncertainty. This book includes notes, glossary and references. (Noel Hendrickson is Director of the Institute for National Security Analysis. Originally published by Proteus.)