Yeah, I just assumed that Indexer's sampling was frequent enough to establish a relatively accurate trend (after all, cFIREsim's own sample size is only 5x greater, since it uses 1-year sample points--or am I wrong about that? Does cFIREsim track intra-year market returns?), but guess not.
Even if Indexer's method did establish a trend, it wouldn't be close to the FIRECalc number. Indexer's method is like asking "for each day in June, what is the chance of the temperature being 90F at 5pm in NYC?" There might be a trend there, with the answer linearly rising from 5% on June 1, to 10% on June 30, as the season gets warmer. But that 5-10% number would be nowhere near the answer for the FIRECalc question, which would be "for the
entire month of June, what is the chance of the temperature being 90F at 5pm on at least one day?" That answer would be more like 80-90%, and would be related to Indexer's number by some probability function I've long-ago forgotten. Increasing the number of samples (measuring the temperature at every hour on every day) doesn't make those two different numbers converge.
Yeah, but that's kinda the point -- that's equally true of the WR at the commencement of retirement, hence velocistar's and arebelspy's point that the knowledge that a 4% WR will (based on history) very likely turn into a 3% WR can psychologically help people to pull the trigger.
From one of your previous posts, I got the feeling we kind of agree on this: playing a psychological trick (under the smokescreen of mathematical logic) to cure people of OMY syndrome may result in the correct "end", but I'm not super-comfortable with saying that end justifies those means. While such a trick might be convincing to people who have only a superficial knowledge of SWRs, it would be far better for them to understand the true nature of SWRs (e.g., the 4% SWR is already a pessimistic number because it is derived from the worst-performing year in history, not because your actual WR is likely to sometime fall below 4%). If I had a young kid, and that kid kept throwing iPhones on the ground, I might eventually resort to some story about a fat man in a red suit to get him to stop, but it certainly wouldn't be my first or preferred strategy.
So sure, you can tell someone "dude, don't wait 'til you have a 3% WR before retiring, because you can retire right now at 4% and there's still an 88.6% chance you'll automatically hit a 3% WR during retirement!" Maybe that convinces him to stop being a wuss, but if he then digs deeper into the math and learns "wait...but now you're telling me that even if I do get lucky and hit that 3% WR in retirement, there's a 50% chance that I'll just fall back to a 4% WR?! brooklynguy is a fuckin' liar, I'm dooooomed!!"