Allowing resort casinos in Miami-Dade County would lead to a spike in crime — from rapes to burglaries — an anti-gaming group charged on Wednesday.

The No Casinos advocacy group, whose membership includes heavy-hitters such as former state Senator Dan Gelber and billionaire auto magnate Norman Braman, based its dire predictions on a new study it commissioned, titled “Casinos and Florida: Crime and Prison Costs.”

Add up all those new crimes, and the study estimates the state will have to spend an additional $3 billion in incarceration costs (housing prisoners and building new prisons) in a 10-year period after resort casinos open in Miami-Dade.

The arrival of such casinos is a big if, as state lawmakers would have to change Florida’s gambling laws. The proposal is being discussed by lawmakers in Tallahassee, but is hardly assured of passage.

Supporters of bringing gambling resorts to South Florida have touted the facilities’ job-creating potential, but in a news conference highlighting Wednesday’s crime study, Gelber chided the industry for its “false promises.”

“Our community needs to focus on the harsh realities,” Gelber said.

According to the study, written by a former attorney for the Florida Legislature and a former state government economist, the reality of new megacasinos would be an 8 percent to 12 percent increase in local crime. No Casinos modeled its analysis after a well-known — but not universally accepted — national study of the casino-crime connection that was published in 2006 in The Review of Economics and Statistics, a prestigious academic journal produced by Harvard and MIT.

That 2006 study analyzed county-level data for all U.S. counties over a 20-year period, comparing pre-gaming and post-gaming crime stats. The study’s authors concluded that counties that added casinos saw crime jump.

Though its scope was impressive, that study does have critics, including College of Charleston Associate Professor of Economics Douglas Walker.

Walker said the fundamental flaw with its crime increase projections was that it did not correctly factor in the droves of tourists attracted by some casinos.

“That’s going to overstate the crime rate,” said Walker, who argues that the academic jury is still out when it comes to casinos and a related spike in crime.

“I don’t know what the answer is, it may in fact be that casinos cause crime,” Walker said. “But the 2006 study...is by no means conclusive on that.”

If one assumes the study’s calculations were sound, No Casinos’ tactic of applying its formula to South Florida requires the further assumption that gambling’s impact here would mimic what took place in other parts of the country. There’s also the tricky fact that South Florida already has a sizable gambling presence, yet the No Casinos study essentially places the region in a “pre-gaming” category now in order to justify the “post-gaming” impact on crime stats if new casinos are approved.

Right now, Miami-Dade and Broward counties have a total of 10 operating casinos — a mixture of tribal gambling properties and “racinos” that combine slots with activities such as horse racing. The proposed destination resort casinos would take things a step further by introducing the full assortment of casino games — adding games like craps and roulette — while also building hotels and convention space designed to lure bet-happy tourists.