It may be an accepted principal when explaining the bubble that just burst, but not for estimating the bottom of the current one, except by those who understand bubbles but are clueless about statistics.
In your statement, you assume the bubble started in 2000, with no basis for the assumption, then go back 1 year, assuming that 1 year before your assumption is the right place to start. Then you come up with a number and it is close to your unsupported assumption, which makes you happy and leads you to believe your assumption is correct.
See, you have to wait for the bubble to stop bursting before you really know where it started. Then you say “it reverted to yada yada.” That’s reversion to the mean.
Your analysis so “freshman-in-college” I can’t believe it. Well, actually I can. I’ve come to expect it.
