Distinguish evidence from priors — in conversation, when saying things like “I think Jack is smart, but not extremely smart” distinguish “I don’t have evidence that Jack is extremely smart” from “I do have evidence that Jack is not extremely smart”. This makes it possible for the recipient of information to combine evidence without double-counting agreed priors e.g. the base rate of extremely smart people in the world.
Salamon and Rayhawk, “Share likelihood ratios, not posterior beliefs”, suggests a few rules for updating on others’ beliefs that may be relevant; most importantly (paraphrased):
Distinguish evidence from priors — in conversation, when saying things like “I think Jack is smart, but not extremely smart” distinguish “I don’t have evidence that Jack is extremely smart” from “I do have evidence that Jack is not extremely smart”. This makes it possible for the recipient of information to combine evidence without double-counting agreed priors e.g. the base rate of extremely smart people in the world.