15 year 2.5% for likely 4% SWR success

[1nvest]

I recall a indication that the prospects of a successful 30 year 4% SWR was at greatest risk if you hadn't achieved a 2.5% annualised real in the first 15 years i.e. a deeper inspection of earlier years sequence of returns risk.

But I can't recall where that arose from. Might have been Bill Bengen - but the Duck (duckgo) doesn't quack.

Anyone else heard/recall such and have the source?

[1nvest]

Found it. Kitces