‘No Boston Olympics,’ a grassroots group opposed to Boston hosting the Olympic Games, is calling on state and local leaders to reject a bid because it could cost the City too much money.

A report released today by No Boston Olympics says it would cost Boston between t$10 and $20 billion to host the 2024 Summer Olympics.

“Boston is already the greatest sports town in the world, but bidding for an Olympics shifts resources away from education and core infrastructure state-wide,” said Chris Dempsey, a No Boston Olympics co-chair, in a statement. “If you want better schools or an improved MBTA, say ‘no’ to the Boston Olympics.”

Written by volunteers opposed to a Boston Olympics, the report uses “top-down” and “bottom-up” analysis to estimate what it would cost to bring the Games to the City.

Top-down analysis of the past eight Olympic Games – four summer and four winter – found it cost host-cities an average of $19.2 billion for the Summer Games, before inflation, with a median cost of $15 billion–a figure that is financially comparable to the Big Dig, No Boston Olympics reports.

Additional, bottom-up analysis looked at the cost of the London Olympics, which are estimated to cost roughly $7 billion, without infrastructure spending included.

The report also highlighted the Sydney Olympics, considered to be the most successful games, which cost $4.7 billion (2014 US dollars), the lowest cost of the last eight games. Still, researchers in Australia “concluded that the Games had a negative economic impact on Australia and New South Wales,” because the Olympics disrupted the normal flow of tourism and commercial activity.

“Whatever we think,” Dempsey said, “let’s play Moneyball instead of throwing a three-week party.”

Governor Deval Patrick and the state Legislature created an 11-member commission to assess the feasibility of Boston hosing the Olympic games. Earlier today, the Boston Globe reports, based on the findings of a special commission draft report, a panel “concluded that Boston could feasibly host the 2024 Olympic Games.” However, it would be a “monumental task.”

The special commission has yet to investigate what it would cost to host the Games. And No Boston Olympics believes a host-city bid could be too expensive – both in terms of dollars and lost opportunity.

“Chicago’s failed bid to win the Olympics is estimated to have cost $80-100 million – and that’s in a losing effort,” said  No Boston Olympics Co-Chair Liam Kerr, in the statement. “We believe that $100 million or $5 billion or $15 billion could be much better spent on education, housing, and transportation.”

Click here for a full copy of the No Boston Olympics report: “Another Big Dig: Establishing a range for the cost of a Boston Summer Olympics.”