Estimating is what you do when you don’t know. ~ Sherman Kent


Last week the Central Intelligence Agency celebrated the 10th anniversary of the Sherman Kent School for Intelligence Analysis. When the school was established by the Directorate of Intelligence (DI) in early 2000, it was not a hard decision to select Sherman Kent as its namesake. Kent dedicated his career at CIA to producing intelligence analysis to support policy decisionmakers. 

Because most any large project has a lot of unknown, the purpose of a project plan in Microsoft Project is to better predict the end result in terms of cost, work, scope and time. One of the things I have had the most difficulty accomplishing over the past 25 years is convincing MS Project users that using the entirety of the techniques (features) in MS Project together, provide a predictive model. Leaving certain techniques out, severely limit and invalidate the model.

Sherman Kent on: The Nature of the Estimate

Let me begin with a look at estimates and the business of making them.

Let me first be quite clear as to the general and the particular meaning of the word “estimate” in the present context. In intelligence, as in other callings, estimating is what you do when you do not know. This is the general meaning. In this broad sense, scarcely an intelligence document of any sort goes out to its consuming public that does not carry some sort of estimate. Field reports are circulated only when someone has estimated that the source is sufficiently reliable and content sufficiently credible to be worthy of attention. Current intelligence items as often as not carry one of those words of likelihood–“probable,” “doubtful,” “highly unlikely,” etc. and so forth–that indicate that someone has pondered and decided that the report should be read with something less than perfect assurance as to its accuracy. An endless number of important sentences in even the basic intelligence category carry the same evidence of this kind of speculative evaluation, i.e, estimating.

But what I have in mind in particular when I use the word “estimates” here are the formal intelligence documents which begin to examine a subject from the point of view of what is known about it, and then move on beyond the world of knowing and well into the world of speculating. When you reflect upon a whole large subject matter–the future of Greece or the armed strength of Communist China, for example–and realize that you cannot begin to know about either with the degree of certainty you know your own name, you reach for the next best thing to “knowing.” You strive for some sort of useful approximation. In pursuit of this you evoke a group of techniques and ways of thinking, and with their help you endeavor logically and rationally (you hope) to unravel the unknown or at least roughly define some area of possibility by excluding a vast amount of the impossible. You know that the resultant, while still a lot better than nothing at all, will be in essence a mix of fact and judgment. Upon occasion it turns out to be almost exactly correct, but at the time you wrote it you expressed yourself with appropriate reservation.

To the extent that your judgment and the many quite subjective things which influence it are now involved, the man who reads this estimate will by no means accept it in the attitude of relaxed belief with which he reads, for example, that “not counting West Berlin, there are ten Länder in the FRG.” It is this form of intelligence document that Hilsman’s respondents were cool about. What follows is an attempt to explain the chill.

Let me ask you to think of one of these estimates in terms of the geometrical form called a pyramid. Think of the perfect estimate as a complete pyramid. At its base is a coagulation of all-but-indisputable fact. With an absolute minimum of manipulation on our part, the facts have arranged themselves to form what is quite clearly the base of a pyramid. They have spread out in the horizontal dimensions to the degree that we pretty well perceive its base area, and piled up in the vertical dimension generally to indicate the slope of its sides.

Knowing the nature of the base of the pyramid, to take an illustrative case, is like saying that we now have enough solid information to know that a photo image we have been wondering about is of an aircraft–not, say, a dairy ranch; more importantly, it is a bomber aircraft, not a transport. As to the other things we want to know about it–its performance characteristics–we are not at all certain. We are, however, in a good position to speculate about them.

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