Navigating confidence–precision trade-offs in assessment

In this reply, we address a comment on our paper “Combining probability with qualitative degree-of-certainty metrics in assessment” (Helgeson et al. Clim Change 149(3):517–525, 2018). Our original paper proposes an incremental systematization of confidence and likelihood language used by the Intergovernmental Panel on Climate Change (IPCC). Our goals were to improve consistency across findings and support use of confidence judgments in decision making. The comment critiques our proposal and recommends against its adoption. We argue that this recommendation is based on two misunderstandings. The first concerns trading off confidence against the precision of a finding (our proposal endorses and systematizes the practice). We defend this practice and attribute opposition to an overzealous Bayesianism inapt for the IPCC context. The second misunderstanding concerns our purported commitment to a specific procedure for producing confidence judgements. We clarify that our proposal makes no such commitment. We also note, contrary to the comment’s claim, that a version of the procedure in question has been used in the IPCC’s Sixth Assessment Report.