An expert in a particular field (a doctor, an actuary, etc.) can advise on the risk of mortality from a specific activity of anywhere between 0% and 100%. At what threshold of risk would the halacha determine whether a particular activity constitutes safek pikuach nefesh?
When experts disagree, would the halacha look at the opinion of a single expert, a simple majority of experts, or another criterion to determine the correct opinion to rely on?