AbstractMuch of the most substantive and in‐depth experience with formal cost‐benefit analysis in the public policy realm has occurred in the context of federal environmental regulation in the United States. This experience has many important lessons to teach in the realm of synthetic biology. Indeed, many of the dangers and pitfalls that arise when decision‐makers use formal CBA to evaluate environmental regulation seem likely to arise in the synthetic biology context as well, sometimes in particularly troubling forms. Unfortunately, while in many instances these concerns may well point toward a rejection of formal CBA for synthetic biology, the experience from environmental regulation turns out to be far less helpful in identifying alternative decision‐making tools. Because the decisions that arise in the synthetic biology context have a fundamentally different structure from decisions about environmental regulation, the most useful alternatives from that context do not map easily onto this new context.It may well be generally true that in the search for decision‐making tools, we should not be looking for a single silver bullet that will work in all public policy realms. Perhaps, instead, different kinds of decision‐making call for different tools. This may be true even within the realm of synthetic biology. I am not entirely sure what the “right” tool is for synthetic biology applications, or even whether a “right” tool exists. But at the end of this essay, I offer a few tentative thoughts about why scenario analysis—a strategic planning tool first developed in the context of military planning following World War II—might be one alternative worth considering.