The math › 3 of 6 · INSTRUMENT
How many have we not seen?
Assumptions, all of them: each incident is noticed independently with the same chance p · we don't know p, so we hold a Beta(α, β) belief about it · scale-free prior on the total. Default k = 21 (the disclosed incidents in the vendor tally above).
k · incidents we've seen
α · weight for "noticed"
β · weight for "missed"
unseen incidents U → (amber = 90% range)