The difference is already becoming apparent, she said. Officers who used to handle 150 cases of all types were getting an arrest alert or two every day, Ahlman said. Now they've got upwards of 350 low-risk cases and are getting alerted to arrests only once a week or so.
Conversely, some officers are assigned much smaller groups of high-risk cases, typically fewer than 50.
Probation and Parole Department researcher Ellen Kurtz said they can't tell how well the program is working yet. A full evaluation will take at least six months, she said. She declined to say how the system rated any of the people on parole or probation who've been put through it.
But these innovations are straining a system that's already suffering from lack of resources, said Louise Carpino, president of the union that includes probation and parole officers.
Paying more attention to these "high risk" cases comes at the expense of all the others, she said. Officers can no longer help low-risk people get off drugs, go to AA meetings, or get a GED.
"I've seen this change people's lives," she said. "But you've got to have a human connection."
Criminologist Todd Clear of City University of New York said helping rehabilitate criminals was the original mission of parole and probation.
There's some evidence that it works, he said. But starting in the 1970s, the system has shifted to controlling people who are considered threatening. There's little evidence this does any good, he said.
Clear says he thinks the new machine-learning technology could tip the debate in either direction. But ultimately, he said, it will work only if it can help figure out how to transform "high risk" people into lower-risk ones.
Another hazard is that while the system isn't expected to be right all the time, it influences how people are treated.
"The main ethical concern," said Richard Bonnie, a law professor at the University of Virginia, "is the possible unfairness to the 'selected' offenders."
If the high-risk people do get more supervision, it means they face a greater risk of being caught in a technical violation that will send them back to prison. Should such power be relegated to a computer?
Berk said he's not worried. "This is not like the movie Minority Report . . . as if we are all fated to do one thing or another," he said, referring to the Tom Cruise film in which police make arrests based on psychics who see crimes committed in the future.
The Philadelphia Probation and Parole Department researchers spoke enthusiastically about plans in the fall to experiment with special classes for the highest-risk offenders, guiding parolees to change their thinking and so their actions through "cognitive behavior therapy."
Berk said he's been asked to design similar systems for Washington and other major cities. Whether it helps cut crime in Philadelphia will be closely watched.
Contact staff writer Faye Flam
at 215-854-4977 or fflam@phillynews.com.
