[jeggers]

Two issues with your calculation: (1) You are considering contiguous 9-year periods across which the 14-person sets can be applied with the 48 years + 25. Because the span of time is recorded history, and with a brief look at the Forbes list, at least 1000 years are covered... or 966 sets of 9-year periods (1000-9-25), rather than 5.

(2) Life expectancy globally across this period of time gives a much wider range.

Overall, your calcs are too narrow to disprove Gladwell's assertion. We'd have to dig more deep into the actual numbers to get the real stats to show how likely/unlikely this is.

[fbbwsa]

you are correct, I skimmed/misread the post. I thought it 75 richest LIVING people (and could not for the life of me figure out why they were using such an old Forbes list...), not in history.

Thats why I was assuming we could assume dead people and those under 25 wouldn't be as relevant and fit all potential candidates to a 50-ish year birth-year block.

Taking any arbitrary 9 year period in a 50 year period and finding that it captured ~20% didn't seem odd to me, which is why I screwed up with my bad argument.

Good catch.