"Scientific Wild Ass Guess" sounds better? I think I'd just stick with "educated guess". I wouldn't even make an acronym out of it.

"SWAG" sets the expectations much better than "educated guess"- you're saying "I got very little idea, but you really want a number, so here's a number". "Educated guess" sounds much more like you've got a good idea, which using the term "SWAG" is trying to avoid.

> I got very little idea, but you really want a number, so here's a number

Where does the "Scientific" come in? Because I really thought it implied having a good idea, which made SWAG seem like an oxymoron.

If your guess is a mathematical formula with assumptions for the inputs, those assumptions can be tested and the formula refined ... It's a SWAG.

You use things like Average/95/99, t shirt sizing, how much work can be done in parallel, 3rd party/client dependencies, ramp up time for a new library ... it's still a wild assed guess but at least there's some basis in reality and you can defend your estimate - show me what I'm wrong about or missing and I'll revise my formula.

Negotiating over the assumptions and inputs is 90% of the battle anyway. Without a model you're standing on sand.

I believe it's juxtaposition for comedic effect.