A group dedicated to opposing Boston’s bid to host the 2024 Olympic Games held its first organizational meeting Wednesday night.  

Smith College economics professor Andrew Zimbalist began the meeting by blasting the Olympics as a disastrous move for Boston. Zimbalist is the author of the new book “Circus Maximus” which dissects the economics of hosting an Olympic games. He told about 100 people gathered in a Back Bay church that one truth of the Olympics is that there are always cost overruns.

“It happens because when the Olympic organizers are trying to convince a political body to support their ideas they always come out first  with a bare bones sketch of what they want to do. Once there’s a political go-ahead  then they start adding the frills and the bells and the whistles  and prices go higher and higher.”

And, he said, cities usually wind up running behind on construction projects.

“So they go to the construction companies, and the construction companies for rush jobs charge more money.”

Boston 2024 says the budget for the games would be four and a half billion dollars, but Zimbalist predicts it will be somewhere between 15 and 20 billion. And he doesn’t believe the denials that public money will be needed.

“Because at the end of the day, the public bodies, whether it’s at the city level or the state level or the federal level, are required by the International Olympic Committee, the IOC, to back up, in case the private money doesn’t come through.”

Zimbalist said that’s what happened with the 2012 games in London. The cost of operating the games was supposed to be paid for by Olympics money, he said, but when they fell short, the city was on the hook for $1.6 billion. And he said they got stuck with another 1.8 billion dollar bill when the developer for the Olympic village walked away.

Ashley Enochs attended the meeting, and stood up to say her concern wasn’t with cost overruns. It was the impact on the neighborhoods.

“We’re having this meeting in Back Bay. Nothing’s going to be knocked down around here. Nothing’s going to be knocked down around here to put in an Olympic venue. And I really want us to focus on reaching out there. And we’re not going to  do that as much if we just keep on talking about how this is going to hit taxpayers.”

Those who would be most impacted, she said, were low-income people who don’t own property, but may have lived here their entire lives.

George Boag of Dracut also stood up.

“The previous speakers, I get the feeling are all kind of left of center. Let me tell you, I ran for office as a tea party Republican, this is an issue that will unite the left and the right.” (applause.)

Boag said the things that concerned him were cost, corruption, and inconvenience.

Of the four U.S. cities in the running for the 2024 games, Boston was the only one with an organized opposition group. One of the group’s founders, Chris Dempsey, told the crowd why their opposition was necessary.

“The boosters are not eager to talk about the cost of the games. They’re not eager to talk about what could go wrong. And groups like No Boston Olympics and others need to be there to say, ‘wait a minute, there are costs here. There are down sides. And there are substantial, substantial risks.’”

Dempsey said the more people know about hosting the games, the less they support the idea. His group plans to push for a voter referendum on the games.

“To this point at least, you have not been an important part of the process. You are not the people they’re trying to convince. They’ve been trying to convince the USOC, now they’ve moved to the IOC level. If we take a referendum strategy, then all of a sudden, they’ve got to give it to you.”

The group also plans to push lawmakers to take action against the Olympic bid. They’re also considering what legal options they can take against the bid, and they may lobby the International Olympic Committee directly.

Boston 2024 plans to hold its first public meeting and release the details of the city’s  bid next week.