Sherman Kent and the scale that translated words into probabilities
For a long time, expressing different levels of certainty with common language was a persistent challenge. 🧮 While numbers handled probability with precision, translating that into words generated confusion. This quest, from the Greeks to today, found a practical solution thanks to an intelligence expert.
The historian who ordered semantic chaos
Sherman Kent, a historian who worked for the CIA's predecessor, noticed a key problem in the 1960s. Reports used terms like probable or unlikely inconsistently. Each analyst interpreted these words in their own way, complicating clear risk assessment. Kent decided to create a common standard that everyone could understand.
The problem Kent identified:- Inconsistent use of probability terms in reports.
- Personal interpretations that generated confusion in evaluations.
- Lack of a common language for communicating risk estimates.
“Ambiguity in intelligence language could be costly. Kent sought to put numbers to words.”
The tool that changed how uncertainty is communicated
His solution was the Sherman Kent Verbal Probability Scale. This tool assigned specific numerical ranges to common expressions. For example, he defined almost certain as 93%, probable as 75%, and unlikely as 30%. The intelligence community adopted this system to communicate estimates with greater clarity and reduce misunderstandings in critical reports. ✅
Key examples from the scale:- Almost certain: Assigned to a 93% probability.
- Probable: Corresponded to a 75% possibility.
- Unlikely: Linked to only 30%.
A legacy with inherent irony
Ironically, the system created to eliminate ambiguity sometimes reintroduces it. Some people debate whether a probable event is exactly 75% or maybe 70%. 🤔 This shows that the human quest to precise the uncertain seems to have no clear end, even with tools designed to achieve it. Kent's work, however, laid a crucial foundation for standardizing how we communicate what we don't know for sure.