We have a few things in common, Daniel Kahneman and I. He’s won only one more Nobel Prize than me. We’re both interested in the psychology of decision making. And we’ve both written a book called Noise. His book is being published in 2021, mine was published in 2019. I feel we could be friends if he knew I existed.

A few of the people who’ve read my book have asked if I’m distressed about this other one coming out with the same title. Actually, I’m delighted. It’s never going to hurt my cause if I happen to be mentioned in the same sentence as this rock star psychologist.

I’ve loved the guy ever since I first encountered his work with Amos Tversky in the course of my CFA studies a quarter-century ago. Kahneman has made a massive contribution to our understanding of where and how we make poor decisions. In his new book, he is deepening our understanding. That’s to be welcomed. 

But, even though our books have the same title, Kahneman and I approach the phenomenon of noise in fundamentally different ways.


The scope of our work on noise is different.

  • Kahneman’s work is panoramic, he’s speaking to all of humanity. The subtitle of his book is A flaw in human judgment. He addresses many fields and occupations, from legal judges to insurance underwriters.
  • In contrast, I’m laser-focused on one field only: investment management. The subtitle of my book is How professional investors can gain the edge. I’m speaking only to investment professionals, no-one else.


We use the same word to signify different things. 

  • For Kahneman, noise refers to the variability and inconsistency of the choices that different people make when given similar conditions from which to choose. 
  • My focus, in contrast, is on the difference in decision quality of the same person (an individual fund manager) when operating under different conditions (high levels or low levels of noise).

My definition of noise is the set of acute disruptions and chronic disturbances that undermine your ability to function well as an investment professional. If you understand the nature and sources of this noise, and if you actively manage your noise levels, then you develop a competitive advantage over other investment professionals who don’t or won’t. Different levels of noise make a difference. That’s what my book’s about.

I hope you read Danny’s book. He’s a smart guy.