Okay, forget considering building a stadium on a site that’s really too small to fit one, because the Oakland A’s just trumped their own crazy yesterday, releasing a report that insists that a new stadium would generate $3.05 billion in economic impact over ten years for Oakland. That’s billion. With a B:

The study, conducted by the Bay Area Council Economic Institute, also concluded that a new stadium would boost annual attendance by roughly one million, up from the 1.5 million or so that the A’s drew in 2016. Building a new ballpark would also produce about 2,000 construction jobs… The $3.05 billion in economic benefit is broken down into $768 million from construction and related spending, $1.54 billion from game-day spending and $742 million from ballpark operations.

Okay, let’s break this down some. The $768 million from construction is uncontroversial, since a stadium is going to cost close to that much to build, though whether it should be counted as a net win for Oakland is another question. (Are all the vendors providing steel for the stadium going to go out and spend their earnings at the local Safeway?) The rest of the study, though — which features a lovely opening photo of Ryon Healy about to be mobbed by teammates excited about all the new economic benefits he’s bringing to Oakland — relies on the assumption that “gate receipts grow by approximately 2x in the first year of operations of a new stadium while concession spending increases at an even higher rate.”

There are a couple of problems with this. One is, obviously, the substitution effect: If all those new fans would have been spending that money elsewhere in Oakland anyway, it’s not a net benefit to the city. The Bay Area Council Economic Institute study takes this into account by discounting new spending by 20% — a number they apparently got by seeing that a previous study for the Detroit Tigers used 25% as the amount of spending that was substituted, then arbitrarily reduced that to 20% because Oakland is likely to have more out-of-towners attending games.

Then there’s that doubling of gate receipts thing. The study actually calculates that MLB teams saw attendance increase an average of 40% in the first ten years of a new stadium — though it puts its finger on the scale by not counting the New York Yankees and Mets for “lack of applicability,” for which read “they actually saw attendance go down in their new stadiums, that’s not going to help our numbers.” I’m not going to re-run their calculations right now, but suffice to say that that’s a lot to expect from a stadium honeymoon period, and isn’t likely to be sustainable over the long term (cf. the Cleveland Indians, who sold out several seasons in a row after their new stadium opened and now can’t draw flies despite a shiny new league championship trophy).

So, in short: If the A’s move four miles down the road from the Coliseum to new digs, some unknown number of additional people might go to A’s games, and some unknown number of them might have otherwise spent that money eating dinner in San Leandro, and some unknown amount of that cash might end up getting recirculated in the Oakland economy rather than just getting pocketed by the A’s owners and players, and — hey, why don’t we just call it an even three billion dollars? And don’t be bothered by the fact that nobody who has ever tried to find evidence of one of these stadium-sparked public windfalls has ever found any — $3 billion! With a B!

Anyway, here’s hoping that the A’s owners are just using the clear plastic binder gambit because it’s available to them, and they’ll end up actually paying for stadium construction and land acquisition and accepting a site that works for the city of Oakland and not just for them, like they say they will. If that happens, I will forgive them all their silly economic projections, though I make no promises to stop making fun of them for them.