van der Bles et al. 2020 PNAS — numeric uncertainty ranges do NOT damage trust in the source

Claim: van der Bles et al. (2020, PNAS 117(14):7672-7683) ran four online experiments plus one field experiment on the BBC News website (total N≈5,780 UK adults). Per the authors' summary: numerically expressing uncertainty "causes people to be less confident in the number itself... but does NOT cause people to lose trust in the source of that number."

Source: van der Bles, Linden, Freeman, Spiegelhalter 2020, PNAS. Peer-reviewed; pre-registered.

Confidence: Verified.

Why this matters for Candid: Defines the safety of "Based on your answers, your situation is High difficulty" — confident at the source level even when the underlying inputs carry uncertainty. The widget can show numeric ranges (and SHOULD where they exist) without damaging credibility.