Blog Post - Views on the Economy and the World

Maxims of Richard Zeckhauser And Errors of Commission

| July 14, 2021

Richard Zeckhauser, my colleague at Harvard Kennedy School, is indeed legendary.  A book by Dan Levy, titled Maxims for Thinking Analytically: The wisdom of legendary Harvard Professor Richard Zeckhauser, has been released today.

I recommend it highly. This is not a collection of tangential papers published together in someone’s honor.  Rather each chapter consists of an immortal maxim of Richard’s together with applications to real-world decision-making, whether at the personal or public-policy level. There are 19 such pithy insights, such as “Think probabilistically about the world,” or “Good decisions sometimes have poor outcomes,” or “Eliminate regret.”  Dan skillfully weaves into each of his chapters concise contributions from a big set of Zeckhauser-admirers, including Max Bazerman, Jason Furman, Hsien Loong Lee, Jennifer Lerner, Barry Nalebuff, Larry Summers, among many others.

My own contribution is to Chapter 10.  Richard’s 10th maxim is: “Errors of commission should be weighted the same as errors of omission.”  At first, this may seem obvious.  But consider the famous “trolley problem” in ethics.  Although the utilitarian or consequentialist answer is to actively divert the trolley to kill only a single person, rather than passively letting it hit five people, many philosophers (the deontologicalists) say that the error of commission is morally worse. Murder is a sin, after all.

The maxim also rejects some guidelines that are themselves treated as obvious in other professions:

“Errors of omission vs. commission in environmental policy,” pp.113-14, in Maxims for Thinking Analytically: The wisdom of legendary Harvard Professor Richard Zeckhauser (2021)

Richard’s maxims are useful corrections to common mistakes in decision analysis that are hidden in what is widely taken to be unassailable common sense. What could be more universally accepted as wise words to live by, in the medical profession and beyond, than the apparent truism, “First, do no harm.” This principle, supposedly based on a line in the Hippocratic oath, seems to say, “errors of omission should be weighted zero, relative to errors of commission.”

For example, if a doctor contemplates a surgical procedure for a dying patient that has a 90 percent chance of fixing the problem and a 10 percent chance of resulting in immediate death, a literal interpretation of “do no harm” would be to forego the surgery and let the patient die shortly. Richard would of course say that the right answer from the probability-weighted average of outcomes is to go ahead with the surgery.

By the way, I have no problem if someone wants to justify “do no harm” as a three-word summary of the idea that surgeons might sometimes be too quick to operate. It would serve as a recommendation to lean toward conservative treatment, thereby counteracting the temptation to “apply your hammer to everything that looks like a nail.”

Public policy applications of Richard’s maxim “Errors of commission should be weighted the same as errors of omission” arise in environmental policy. Some, especially in Europe, have a fear of new and unfamiliar technologies in general. The claim that the burden of proof lies with the innovation, rather than symmetrically with the status quo, sometimes goes under the name of the “precautionary principle.” It helps explain the tendency to forget to compare the worst-case risks of the new technology with the known downsides of the old technologies.

One example is genetically modified organisms (GMOs). It is true that a fundamentally new technology tends to pose unknown risks. Let us say that there is some small probability of doing some harm (an error of commission). That is no excuse for neglecting to weigh in the balance the known risks of the existing technology (an error of omission). In the case of genetically modified crops, the costs of doing without them include a greater need for insecticides and possible food shortages in poor countries.




For more information on this publication: Belfer Communications Office
For Academic Citation: Frankel, Jeffrey.Maxims of Richard Zeckhauser And Errors of Commission.” Views on the Economy and the World, July 14, 2021,