Words of estimative probability (WEP or WEPs) are terms used by intelligence analysts in the production of analytic reports to convey the likelihood of a future event occurring. A well-chosen WEP gives a decision maker a clear and unambiguous estimate upon which to base a decision. Ineffective WEPs are vague or misleading about the likelihood of an event. An ineffective WEP places the decision maker in the role of the analyst, increasing the likelihood of poor or snap decision making. Some intelligence and policy failures appear to be related to the imprecise use of estimative words. History Intelligence In 1964 Sherman Kent, one of the first contributors to a formal discipline of intelligence analysis addressed the problem of misleading expressions of odds in National Intelligence Estimates (NIE). In Words of Estimative Probability, Kent distinguished between ‘poets’ (those preferring wordy probabilistic statements) from ‘mathematicians’ (those preferring quantitative odds). To bridge the gap between them and decision makers, Kent developed a paradigm relating estimative terms to odds. His goal was to "... set forth the community's findings in such a way as to make clear to the reader what is certain knowledge and what is reasoned judgment, and within this large realm of judgment what varying degrees of certitude lie behind each key judgment." Kent’s initiative was not adopted although the idea was well received and remains compelling today. Policy and intelligence failures related to WEPs An example of the damage that missing or vague WEPs can do is to be found in the President's Daily Brief (PDB), entitled Bin Laden Determined to Strike in US. The President’s Daily Brief is arguably the pinnacle of concise, relevant, actionable analytic writing in the U.S. Intelligence Community (IC). The PDB is intended to keep the President informed on a wide range of issues, the best analysts write it and senior leaders review it. This, the “August 6 PDB,” is at the center of much controversy for the USIC. The August 6 PDB began with not only a vague warning in the title, but also continued with vague warnings:“Bin Ladin since 1997 has wanted to conduct terrorist attacks in the US” (CIA, 2001, para. 1); “Bin Ladin implied...that his followers would ‘bring the fighting to America’” (CIA, 2001, para. 1); Bin Ladin’s “attacks against...US embassies...in 1998 demonstrate that he prepares operations years in advance and is not deterred by setbacks” (CIA, 2001, para. 6); “FBI