Accounting for systematic risk in benefit-cost analysis: a practical approach

Circular A-94 specifies how analysts should discount costs and benefits of government projects, and thus how to account for risk. In this paper, we argue that the methods mandated by A-94 properly account for non-systematic and term risk, but not for systematic risk. A numerical example illustrates how improper accounting for systematic risk produces misleading results and social welfare loss. We conclude by proposing a simple modification of A-94's procedures that would allow analysts to at least partially account for systematic risk.