With the Nationals heading to the World Series for the first time in franchise history, D.C. tourism officials are positively giddy about the prospect of a revenue injection.

Hosting at least two World Series games will fetch the District an estimated $6.5 million in spending, according to an announcement from Destination D.C.—the city’s official marketing organization.

“Beyond the great emotional lift, the World Series is going to translate into lots of economic activity for our city,” said Gregory McCarthy, the Nationals’ senior vice president of community engagement, in a press release. “Residents will be employed; the city will collect millions in taxes and local businesses will benefit. We’re delighted that the city’s investment in baseball is yielding such benefits.”

D.C.’s estimated $6.5 million windfall from hosting the World Series is “inconsistent with every shred of evidence that economists have generated over the last 20 years,” says economist Brad Humphreys.

The rosy projections have a ring of truth to them: Thousands of baseball fans will spend on hot dogs, tallboys, and Uber rides when the Nationals face the Houston Astros this weekend. And with an estimated 15 percent to 22 percent of visitors coming from out of town, according to Destination D.C., hotels will get a big boost, too.

“We’re now seeing a spike in visitors that are coming into the city,” said Destination D.C. President Elliott Ferguson.

But economist Brad Humphreys calls the estimates “propaganda.”

“It’s inconsistent with every shred of evidence that economists like me have generated over the last 20 years,” said Humphreys, who has studied the economic impact of postseason games on host cities.

Projections like this, he says, are used to justify hefty public spending for sports stadiums, like the nearly $700 million—or $1 billion, with interest—D.C. spent to help build Nationals Park.

“They want more subsidies from the government,” Humphreys said. “Every local development person or team public affairs person always issues these sort of statements … and they’re always taken at face value. Even though it’s completely inconsistent with the evidence.”

The Substitution Effect

What the evidence actually shows, economists say, is that the spending postseason play sparks typically isn’t “new”—it’s just money spent on one thing instead of another.

When calculating the economic impact of major sporting events, said economist Robert Baade, you have to account for the “substitution effect.”

Most people who attend the games this weekend will likely come from within a 25-mile radius of Nationals Park, not far-flung locations, Baade said. And the money they spend at the ballpark is money they won’t instead spend on, say, local butter chicken or local candles.

“You have to think about what spending on these playoff games offsets in the way of spending that would otherwise occur in the Washington, D.C., area,” Baade said.

In an analysis of 129 MLB playoff series from 1972 to 2001, Baade and economist Victor Matheson concluded that despite optimistic projections from Major League Baseball and other boosters, “any economic benefits from the playoff[s] are small or nonexistent.”

Also unclear is how much tourist income will stem directly from the World Series. Research has indicated that stadiums generally don’t draw lots of tourists on their own—especially in cities like D.C., which are already tourism magnets, Humphreys said.

“If people came to Washington, D.C. from out of town as tourists explicitly to go and see the World Series, that will generate new economic benefits. But the problem is, there’s no evidence to back any sort of statement that said 20 percent of the crowd at these World Series games are going to be traveling from out of town,” he said.

Unlike the Super Bowl, a major one-time event that’s planned far in advance, World Series games happen across multiple dates in multiple places, with little notice. “There’s just not enough time to make travel plans,” Humphreys adds.

‘This Is Not A Costless Thing’

Meanwhile, costs associated with World Series games are unknown or difficult to calculate.

One potential loss stems from the effect that the World Series might have on other tourism in the District, as potential visitors avoid traffic or crowds from the event. And there are city expenses associated with the games—including policing, transit personnel, and cleanup.

“This is not a costless thing,” Baade said. “For Washington, D.C., to accommodate the event, it’s going to require a lot of additional police, cleanup expenses, and so forth. And who is responsible for all that stuff? Typically, it’s the community.”

A spokesperson for the Metropolitan Police Department did not return WAMU’s request for information about expenses associated with major sporting events, and a spokesperson for the Office of the Chief Financial Officer said there is no published data on how much the city has paid for similar events in the past.

Those costs shouldn’t be ignored, Humphreys said—especially because research has shown a relationship between crime and major sporting events. One recent paper in the Journal of Sports Economics showed “significant increases in a variety of crimes”—including minor assaults and destruction of property—during St. Louis Cardinals home game days.

“That costs money,” Humphreys said. “There’s going to be officers working overtime. There’s all the crowd control, all the traffic control. And those policing costs would not be incurred if the World Series games weren’t played.”

Intangible Benefits

All this isn’t to say there are no benefits to the Nationals playing in the World Series.

The temporary pluses are clear: Businesses near the stadium will almost certainly see a boost during the games; Uber and Lyft drivers will collect tips; merchandise vendors — including those selling unlicensed Nats gear—will make money. Somehow, Walgreens might benefit, too.

And even number-crunching economists recognize there are intangible, psychic benefits.

“I don’t dispute the idea that there’s a lot of euphoria,” Humphreys said. “D.C. is probably an electric place this week.”

But the academic is still irked by the torrent of rosy economic impact estimates that circulate during every postseason run.

“Isn’t it enough to just say, ‘This is great for the community because it’s getting us all to pull together and get behind the team?’” he said.

This story originally appeared on WAMU.