Canadians probably know much less about guns, gangs and murder than Americans, and Malcolm Klein knows more than most Americans. The renowned criminologist and police consultant has good news and bad news for Canadians worried about the gun battles on the streets of Toronto. First, the good news. "Gang activity goes through cycles," he says. "All the time. Different cities have different cycles." Mr. Klein hasn't studied the situation in Toronto but when told that gun killings -- most or all of them gang-related -- jumped from 24 to a record 52 in 2005, he recognizes the pattern. "It's a spike," he says. "I would expect it to come down fairly rapidly." Unfortunately, that's the only good news Mr. Klein has to offer. Everything else he has to say is bad news for politicians and ordinary Canadians looking for a way to end gang violence. There simply are no proven solutions, says the professor emeritus at the University of Southern California and author of The American Street Gang. "I keep getting the phone call: 'What's the answer?' And I'm sorry but we don't know because most of the programs have not been independently evaluated. The ones with the greatest claims of success are the ones with the least data to support that. And the politicians don't want to hear that. They need something quick." And what happens when he says this to politicians? "I don't hear back from them. That's literally true. It's not what they want to hear." Mr. Klein's bad news may come as a surprise to Canadians who have been following the media in recent weeks. Several reports have highlighted anti-gang programs in various U.S. cities which, the reports said, were fantastically successful. The most famous case is New York City in the 1990s. Under mayor Rudy Giuliani, the city introduced a crackdown on minor offences such as vandalism -- following the "broken windows" theory that tolerance of minor disorder promotes more serious offences -- and created a sophisticated computer tracking system called "Compstat." New York's horrific murder rate plummeted, along with most other crimes, and Mr. Giuliani became known worldwide as the man who had discovered the secret to crime. Then there was Boston's Operation Ceasefire, which blanketed gangster-ridden neighbourhoods with police officers who warned young thugs of the severe punishments to follow if they didn't change their ways. At the same time, community leaders mobilized resources to reach out to troubled youths and offer them mentoring and social programs. Gang murders plummeted. The media called it the "Boston Miracle." Many other American cities notched up similar successes. Mayors boasted. Police crowed. The media applauded. And now Canadian politicians, police and journalists are repeating these tales of crime vanquished. But Mr. Klein says claims of victory are nonsense. "There are no demonstrated successes with respect to gang homicides," he insists. In city after city, he says, programs were implemented as the cycle of gang violence worsened. When it relented, officials simply pointed to the improving numbers as proof that their programs worked. What was missing was evidence that it was the programs that caused the drop rather than countless other factors in play. One simple way to test the effect of a program is to compare the crime drop in the target with results in other parts of the city, or in other cities, that didn't put the program in place. The mayors and police chiefs bragging about their results rarely did that, even though crime dropped rapidly throughout the United States in the 1990s. As a result, cities across the U.S. claimed to have found the magic solution -- and each solution was different. Some credited youth curfews. Others said it was community policing. Detroit's police chief said it was thanks to his efforts to get the neighbourhoods involved. The mayor of East St. Louis said it was all due to having more officers and more anti-gang patrols. Houston's police chief said it was storefront police stations in crime hotspots. And on and on it went. The case of New York City became world famous not because it was unique but because the Big Apple is the world's media centre. None of these claims of victory has stood up to the tests of time or scrutiny. Many of the cities that once claimed to know the solution have since suffered rising murder rates. Budget cuts are blamed. Or a lack of focus. "There's always an excuse," says Mr. Klein. But more damning is the work of criminologists. Few of these programs have been subjected to methodical, scientific evaluation, says Mr. Klein. But those that have been studied have failed. None of this has given Canadian politicians pause. There is, despite the noisy rhetoric about gun crime, a rough consensus. Everyone from Jack Layton to Dalton McGuinty to Stephen Harper agrees that punishments have to be toughened. And everyone agrees there have to be more social programs. Mr. Klein isn't impressed. "In other words," he wryly sums up this approach, "hit both ends and pray."