Base rate first, then your probability, then how you'll know. Don't revise it later; score it.
?Forecast: Will the new onboarding flow lift week-one activation above 40% for the cohort that signs up in June, measured exactly the same way as last quarter's cohort?
How often does this kind of thing happen? (the base rate, and where it comes from)
My probability
%
Resolves by: 30 June
What would change my mind before then
At the return: what happened, and the score