Kennon-Green & Co. Fiduciary Financial Advisor, Wealth Management, Global Value Investing

Mental Model: Cui Bono

Lucius Cassius Longinus Ravilla was a famous Roman judge, who, according to Marcus Tullius Cicero, was regarded as an “honest and wise” man.  He was known for a habit of constantly asking the question, “Cui bono?“, which roughly translates into “who benefits?”.

In a crime or a political scheme, Lucius Cassius believed the best place to start was by looking at, not necessarily the most likely suspect, but to the person or people who were in a position to benefit most from the event.  Many times, this benefit came in the form of financial gain (follow the money), but not always.

Cui bono is really a way of acknowledging that incentive systems drive human behavior and that to understand the probable outcomes of a system, one need only look at the people to whom the benefits flow.  The big questions you need to ask or answer, depending upon your task, are:

  • Who benefits?”,
  • How do they benefit?”, and
  • “By what action do they benefit?”.

Going around and asking yourself, “Cui bono?”, can help you discover hidden motives, create incentive systems for your businesses, understand the way the world is interconnected, and so much more.  It is an incredibly useful mental model that can help revolutionize your life, properly harnessed.  Its effectiveness is matched only by the deceptive simplicity.