This article summarizes the methodology used by the interagency working group to develop a range of SCC estimates for use in regulatory decision making (in many instances, borrowing language directly from the interagency report), discusses how these SCC estimates can be used to inform regulatory decisions, and identifies priorities for future research. We note at the outset that developing estimates of the SCC requires making many assumptions, and it is inevitable that some readers will not agree with all of them. Our aim here is to describe these assumptions in sufficient detail to enable readers to conduct their own research and suggest improvements so that future efforts to revise the SCC will rely on a methodology that improves on the one described here.