1. CHICAGO
I
t was an unusual encounter from the
start. On a cold evening in February, Chi-
cago police officer Maria Peña knocked
on the door of a house in one of the city’s
most crime-ridden neighborhoods. She
wanted to talk to a leader of the Latin
Kings, a gang on the city’s South Side, as well as
his mother. Ms. Peña was not there to question
or arrest the man. She wanted to save his life.
The gang leader opened the door. “He was a
little wary to see me,” says Peña, commander of
the Chicago Police Department’s 10th District.
Nevertheless, his mother welcomed Peña and
several other local officials. She invited them
to sit around the kitchen table with her son, his
girlfriend, and a 6-year-old niece. The kitchen
was tidy, the atmosphere cordial. But the talk
turned blunt quickly.
“I looked at the mom and said, ‘Honestly,
do you want to bury your son?’ ” And, she told
her, it might not be just him. Peña recounted a
recent retaliation shooting in the neighborhood
in which an innocent bystander – a 10-month-
old girl – fell victim.
“Do you want your little granddaughter be-
ing the next victim?”
She urged the son to jettison his gang-re-
lated activities and offered a variety of social
services to help him do it.
Since then, Peña is not sure if the gang lead-
er changed his ways or whom he associates
with. What she does know is that he’s still alive
– and shootings related to the Latin Kings have
stopped, at least temporarily, in her district.
Peña was basing her warnings in part on
intelligence the police had gleaned from com-
puter algorithms. Her visit on that raw night
was part of a pioneering attempt by the Chi-
cago Police Department (CPD) to harness the
STORY BY MARK GUARINO / STAFF WRITER
PHOTOS BY MELANIE STETSON FREEMAN / STAFF PHOTOGRAPHER
Chicago Police Cmdr. Maria Peña speaks to officers
before they head out on patrol in the 10th District,
where they have been engaging more with residents.
Chicago police officer Marco Gallegos waves at
two women, making sure they’re OK, as he patrols
a neighborhood on the city’s South Side (opposite
page).
VNEXT PAGE
IN CHICAGO, BIG DATA
WALKS THE BEAT.
HOW POLICE ARE TAPPING
ALGORITHMS TO CURB
VIOLENCE.
CAN MATH STOP MURDER?
THE CHRISTIAN SCIENCE MONITOR WEEKLY | JULY 21, 2014 27

2. power of Big Data to stop crime before it
happens.
Armed with a plethora of statistics on
everything from gun violations to individual
parole and arrest histories, police here are
trying to create a national model that will
help them predict where shootings might
occur and who might be involved – both
victims and offenders. Then they use the
information to reach out to people in the
neighborhoods in the hope of preventing
the guns from ever being brandished.
“I don’t think the families always know
these guys are out there doing what they are
doing,” says Peña. “When you have these
kind of conversations with their families,
and the [gang members] see the hurt in their
mother’s eyes, I think that hurts them, be-
cause the family means everything to them.”
Chicago’s experiment is part of an
emerging new movement of preventive
policing that is sweeping through precinct
houses across the country and even around
the world. Cities from Los Angeles to Atlan-
ta, Seattle to Santa Cruz, Calif., are trying to
harness the power of math to curb various
forms of crime, whether it’s robbery, gun vi-
olence, or drug dealing. Authorities in Kent,
England, are using sophisticated computer
models to guide police, too.
But the CPD is pushing the science in
new directions. Beat cops and veteran pre-
cinct captains in the nation’s second largest
police force are teaming up with number
crunchers and leading university crime re-
searchers in their quest to better understand
gun violence and engage with neighborhood
residents.
Chicago’s initiative, though still nascent,
has shown some success so far. Since last
July, police have carried out 66 house calls
similar to the one Peña made. In only two
cases were gang members they visited later
involved in shootings – which is progress
for a city reeling from a national reputation
for bloodshed.
It’s also one reason the initiative here is
now being looked at by a number of police
departments in other cities, such as New
Orleans and Toronto. While no one sees
Big Data as the answer to crime – and the
program isn’t without controversy – people
here see it as a powerful new tool to combat
urban violence.
“Police in major American cities have
endured generations in which good
and serious people came to work ev-
ery day and felt they were not doing any
good in solving the violence issue...,”
says David Kennedy, director of the
Center for Crime Prevention and Control at
the John Jay College of Criminal Justice in
New York, who is involved in the Chicago
project. “Now, the fact that you can do good
and help people and possibly save lives is
transformational.”
Preventivepolicingmovescopwork one more
step from the era of batons to the era of
bits and bytes. In the 1970s and ’80s, many
cities dealt with a surging homicide problem
by trying to sweep it off the streets. Police
flooded besieged neighborhoods. They
made large numbers of arrests. Courts sent
the criminals to jail – often for substantial
periods of time.
Then came the era of community po-
licing, in which police were more rooted
in neighborhoods, both protecting and
interacting with residents. This approach
was less reactive, adding an element of
preventiveness to law enforcement. Now
comes preventive policing, which combines
enforcement, community engagement, and
analytics. It’s what Garry McCarthy, Chica-
go’s police superintendent, calls “commu-
nity policing almost on steroids.”
In Chicago, the shift to a more num-
bers-based approach began with the ar-
rival of Mr. McCarthy, whom Mayor Rahm
Emanuel appointed superintendent three
years ago. A beefy “cop’s cop” as comfort-
able around numbers as he is doing roll call,
McCarthy came at an inauspicious time: The
city was dealing with the aftereffects of a
police torture scandal that was continuing
to siphon millions in settlement fees. The
police union was upset at budget cuts and
declining manpower, and Mr. Emanuel
was intent on shedding the label “murder
mayor,” the moniker critics gave him when
the number of homicides
spiked above 500 his first
year in office.
At the outset, McCarthy
represented something
different for Chicago: a
superintendent from out-
side the CPD ranks with a
background in crime statis-
tics. He had overseen the
highly touted CompStat
program in New York City,
which created a new way
of managing crime num-
bers and holding precinct
commanders accountable.
Later, while police superin-
tendent in Newark, N.J., he
saw homicides fall 28 per-
cent on his watch. Early in
his new role in Chicago,
McCarthy did something
unheard of in this city where top officials
operate with a tribal allegiance to each
other: He apologized for decades of racial
targeting by the police.
“What he said was, ‘I get it and I’m sorry
and we’re going to try to do better.’ No one
has said that,” says Andrew Papachristos,
a Yale University sociology professor who
grew up in Chicago. “McCarthy has moved
the culture of the police into a place that
keeps Chicago in the front, and not in the
middle, of the pack.”
At the core of Chicago’s new approach
is both collaboration between cops and ac-
ademics and the numbers they gather. Just
as the social network model is effective in
helping create a portrait of Facebook users
– their tastes, habits, and the people they
interact with – the data analysis in Chicago
is giving beat officers a more comprehen-
sive understanding of the neighborhoods
they police.
McCarthy says incorporating the sta-
tistics into preventive policing will move
Chicago away from targeting an entire
community to focusing on individuals most
likely to either cause, or fall victim to, gun
violence. In an interview, the superintendent
says that accountability is no longer just
the domain of district commanders: Beat
officers are now being trained to use data
to figure out where violence might erupt
and how to stop it.
“I see what we are doing in Chicago as
creating a model that is really going to a
whole other level of intelligence-based po-
licing,” he says. “It requires a new way of
thinking.”
The marquee program is the Chicago
Violence Reduction Strategy, a partnership
funded by the MacArthur Foundation and
led by John Jay College, with Yale Univer-
sity, the University of Chicago, and other
academic institutions playing major support
roles. Although currently used in only four
police districts on the city’s South Side, the
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‘WE CAN SHOW [FAMILIES], WITH ALMOST
CERTAINTY, THE PROBABILITY OF THEIR
SON OR BROTHER OR GRANDSON BEING THE
NEXT GUNSHOT VICTIM BASED ON THEIR
SOCIAL NETWORK.’
– Chris Mallette, head of the Chicago Violence Reduction Strategy program at John Jay College
28 THE CHRISTIAN SCIENCE MONITOR WEEKLY | JULY 21, 2014 THE CHRISTIAN SCIENCE MONITOR WEEKLY | JULY 21, 2014 29
People walk through Chicago’s Englewood neighborhood, a crime-ridden area, as a
police vehicle cruises by (opposite page).
David Kennedy, in his office at the John Jay College of Criminal Justice in NewYork
(left), helped develop a database about Chicago gangs.
ANN HERMES/STAFF

3. strategy is expected to spread.
Fashioning the program required under-
standing Chicago’s gang culture. Decades
ago, gangs here were large criminal organi-
zations that dominated expansive areas of
turf and fought for control of the drug trade.
Today, they are neighborhood factions that
control only a few blocks. According to the
Chicago Crime Commission, 70 to 100 gangs
now inhabit the city, encompassing about
100,000 members. Many have different
and changing reasons for existence, which
makes it hard for the beat cop to under-
stand, much less control, them.
Enter Mr. Kennedy and the digiteers. His
team helped the police create a database
that monitored which gangs were active,
which were quiet, which were fighting – and
with whom. “You can’t even understand
what is going on until you have that level
of specificity,” he says.
To get that information, John Jay re-
searchers interviewed key personnel across
the city – mainly beat cops – about what
they saw on the streets and built that into
the current CompStat system.
Many seasoned officers were reluctant
to cooperate. They didn’t understand why
they needed to be that granular about gang
activity, and many were more apt to trust
their instincts than a computer algorithm.
“Getting [the value of this] across can be
really hard, especially in a city like Chicago,
where you have four generations serving
in the same police district,” says Professor
Papachristos of Yale.
But he says views began to change when
the John Jay team returned with the results:
a systematic snapshot of gang factions that
could yield predictions of where violence
might break out next.
Whilesomeofficersstilldon’tembrace the new
approach, the results have been reason-
ably encouraging so far: Police data show
shooting incidents – both fatal and nonfatal
– dropped 24 percent in 2013 compared with
the year before. Murders fell 18 percent,
from 503 to 414.
Shooting incidents through June 30
of this year ticked up 5.5 percent, though
the number of murders dropped 5 percent
compared with last year, according to the
CPD. Still, crime remains stubborn: The city
experienced 82 shootings – and 14 deaths –
over the July 4th weekend alone.
The numbers overall, while not perfect,
reflect a tactical shift in how police respond
to shootings. In 2013, Papachristos and Yale
colleague Christopher Wilderman calculated
that, between 2006 and 2011, the homicide
rate of “a high-crime African American com-
munity in Chicago” was 55.2 per 10,000
people. That number was about four times
the citywide rate during the same period.
The old mind-set would suggest that
this neighborhood was a dangerous place
and that many people there were at risk
of being either a victim or perpetrator of a
crime. The traditional response might have
been to dispatch a large number of police
to the area, turning the neighborhood into
something of a battle zone.
But Papachristos and Mr. Wilderman’s
data showed that a very small percentage
of the population was probably causing all
the problems and a lighter, more targeted
police footprint would be more effective.
According to their research, arrest records
show that 85 percent of all gunshot homi-
cide victims had at least one previous arrest.
Victims and perpetrators of violence also
tend to know each other and operate within
the same social networks. Using both ar-
rest and homicide records, the researchers
found that the population of the community
that had been arrested during the five-year
period consisted of 24,110 people, about 30
percent of the total population.
Drilling down further, they calculated
that 41 percent of all gun homicide victims
were located within the social network of
arrestees. The percentage that those vic-
tims represented within the community as
a whole was 3,718 people, or only 4 percent
of the population.
“Crime is more concentrated within net-
works of people than actual places,” says
Papachristos. “So all of a sudden you’re
talking about 70 to 80 percent of shootings
taking place in networks that represent just
3 to 5 percent of the population. Those at
risk are a couple hundred people. You now
have a sense of who they are.”
Knowing the numbers is one thing. Getting
people to not pull out their guns is another.
Chicago police are taking several steps to
try to head off violence before it happens,
which may be the most difficult part of pre-
ventive policing.
They have expanded “call-ins,” group
meetings with repeat offenders on probation
or parole, during which they remind them
of the risks of committing another crime.
The city has stepped up foot and bicycle
patrols in 20 high-risk zones – ones that rep-
resent just 3 percent of city land but account
for 20 percent of gun violence. Authorities
have also put into place a system to solicit
feedback from crime victims about their
experience with the police.
“When you talk to the public, yes, they
want crime reduced, but they are more con-
cerned about fairness and respectfulness
with their interaction with police,” says
Dennis Rosenbaum, a criminologist at the
University of Illinois at Chicago who has
helped oversee the feedback program.
“When the public feels ... the police are
being fair in their authority and aren’t judg-
ing them on the basis of race, gender, and
ethnicity, they are much more likely to co-
operate, much more likely to provide them
with intelligence to solve crimes,” he adds.
The most recent and perhaps revolution-
ary development in the CPD’s outreach ef-
fort is the door-to-door campaign, such as
the one officer Peña was a part of.
Years ago, the scene would have been un-
imaginable: The doorbell rings at the home
of a gang member who has been arrested
multiple times. An officer says a district
commander wants to chat with the man
and his family. Can they come in?
Using a formula created by Papachris-
tos and his team, the police have drawn up
a “hot list” of people to visit who may be
most at risk of becoming either the next
offender or victim. It is based on an analysis
of individuals’ criminal histories, prison re-
cords, open court cases, and victims’ social
networks.
Police present the visit as an informa-
tion session and an opportunity for change.
Accompanying the district commander are
representatives from social agencies who
offer to connect the family with health-
care services, classes to earn a high school
equivalency certificate, or job-training and
placement programs.
The officer also conveys something more
sober: what the legal consequences would
be if a person with that kind of record – and
the police detail what the individual’s record
is – were to commit another crime.
“We just lay it out like that with them,
and close by saying the people of your
neighborhood do not want violence – put
down the gun,” says Cmdr. John Kenney,
executive director of the CPD’s Bureau of
Organizational Development, which runs
the custom notification program.
The visitors make sure the others around
the kitchen table hear about the individual’s
rap sheet, too, and what the consequences
of more criminal activity would be for him
and the family.
“It’s terrifying to the families,” says Chris
Mallette, executive director of the Chica-
go Violence Reduction Strategy program
at John Jay College. “We can show them,
with almost certainty, the probability of
their son or brother or grandson being the
next gunshot victim based on their social
network.”
Noteveryoneisenamoredofpreventive polic-
ing, however. Some doubt it will ever have a
meaningful effect on lowering gun violence.
Others worry that it is just a distraction from
what is ultimately needed to improve some
inner-city neighborhoods.
“Much like any other program in Chi-
cago, they are not dealing with the crux of
the problem, which is poverty,” says Tracy
Siska, executive director of the Chicago Jus-
tice Project, a nonprofit group. Police may
offer counseling and social services during
interventions, but Mr. Siska says those are
hollow choices.
“You are not getting a guy out of a gang
until you bring him a job,” he says. “I think
[house calls] are a decent idea, and in the
short term, they may have an impact. But
it’ll only become long term if you can get
those people out of those lifestyles.”
Johnny Outlaw believes they need jobs,
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‘[GANG MEMBERS] SAY, “I’M TIRED OF SHOOTING
PEOPLE, I’M TIRED OF ROBBING PEOPLE. I WANT TO DO
SOMETHING WITH MY LIFE.” I SAY, “IF YOU WORK WITH
ME, WE’LL FIND YOU A JOB. BUT YOU NEED TO PUT
DOWN THAT GUN.” ’
– Johnny Outlaw, who provides legal services and helps offenders find jobs
30 THE CHRISTIAN SCIENCE MONITOR WEEKLY | JULY 21, 2014 | JULY 21, 2014 31
From top: Chicago resident Sean Channell, who
says crime has gotten worse since he moved to
Chicago’s Roseland neighborhood in 1970, wears
aT-shirt that reads‘Stop the killings.’ Chicago
police detain and handcuff a man in Roseland.
He was eventually released.Young men play in
a basketball tournament sponsored by Kids Off
The Block, a Chicago nonprofit that offers youths
alternatives to gangs and drugs.

4. too, but thinks the new police initiative is a
definite step in the right direction. He leads
an effort to find work for repeat offenders
and provide them with legal services. In
private, many gang members tell him that
they want to put down their guns but either
are afraid of retaliation or don’t know how
to go straight. Mr. Outlaw says that he’s
had “top-flight gangbangers” break down
sobbing in his office – “physical tears out
of these cats” – because they feel they’re
out of options.
“They say, ‘I’m tired of shooting people,
I’m tired of robbing people. I want to do
something with my life.’ I say, ‘If you work
with me, we’ll find you a job. But you need
to put down that gun,’ ” he says.
They show up at Outlaw’s match-
book-sized office at Teamwork Englewood,
a nonprofit that partners with the CPD, on
the campus of Kennedy-King College. Out-
law has gone out with Chicago police on
some of their house visits, wearing a bul-
letproof vest over one of his natty suits. He
has transitioned gang members into jobs
ranging from manual labor at warehouses
to driving trucks cross-country.
Others fault Big Data policing for putting
a new face on an old problem: profiling.
Critics argue that a person’s past shouldn’t
define what he will do in the future – that a
person shouldn’t be stigmatized or singled
out for his or her rap sheet.
But police here refute those arguments.
“Profiling is stopping someone because of
their race or color or creed,” says McCarthy.
“We’re doing an empirical analysis using a
scientific formula, which is quite the oppo-
site of profiling.”
In fact, he says, the Big Data approach
shows that the vast majority of people in
troubled neighborhoods are not doing any-
thing nefarious, prompting police to view
‘I SEE WHAT WE ARE DOING IN CHICAGO
AS CREATING A MODEL THAT IS REALLY
GOING TO A WHOLE OTHER LEVEL OF
INTELLIGENCE-BASED POLICING. IT
REQUIRES A NEW WAY OF THINKING.’
– Garry McCarthy, Chicago’s police superintendent
VFROM PREVIOUS PAGE
CORRECTION
The location of the University of Virginia
was incorrectly identified in the July 7 & 14
cover story about makerspaces. The correct
location is Charlottesville.
the communities as less of a threat.
“What it should be teaching us is ev-
erybody in Chicago is not a criminal,” says
McCarthy. “If 5 percent of the community is
responsible for violent crime, then 95 per-
cent of the individuals are good people, and
that provides a larger understanding of the
community, which often goes unsaid.”
In the end, the effectiveness of the new
wave of policing will likely hinge on one
thing: whether it reduces crime. While some
of the initial results are promising, many say
it’s too early to determine how much – or
even whether – it will reduce violence. But
what is certain is that Chicago will provide
one of the nation’s premier tests of how well
the new science of policing works.
Already, it’s got the department thinking
more creatively about preventive law en-
forcement. It’s changing police perceptions
of neighborhoods. McCarthy, for one, has no
doubts about what the denouement will be.
“I think this is what every police depart-
ment in the country needs,” he says. “This
can be used anywhere and can really move
the scale.” r
32 THE CHRISTIAN SCIENCE MONITOR WEEKLY | JULY 21, 2014
Chicago police officer Marco Gallegos walks
through Chicago’s LittleVillage neighborhood,
where he often checks in on local businesses.