Origin of the expression "origin of the expression"

Mostly a joke, but wouldn’t it be cool to have the ultimate “origin of” directory that nobody could dispute? Is Wikipedia it these days? Were any of those heavy books in pre-Internet days really all that well-researched? How many etymology references are just somebody’s WAG?

As as user of such reference material, rate yourself on how much you believe their findings to be beyond dispute:

  1. less than 10% sure
  2. 10-25% sure
  3. 25-50% sure
  4. 50-75 % sure
  5. 75-90 % sure
  6. 100% dead certain

I’m at 4, just because that’s pretty much how I relate to opinions in general.