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Prisoners in Jail With Biometrics: An Experiment in a Navy Brig
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NIJ
Journal No. 253 January 2006
Tracking Prisoners in Jail With Biometrics: An Experiment
in a Navy Brig
by Christopher A. Miles and Jeffrey P. Cohn
About the Authors
Christopher A. Miles is a Senior
Program Manager for Research and Technology at NIJ. Jeffrey
P. Cohn is a freelance writer/reporter.
Keeping track of inmates within a prison or jail is a constant
challenge, especially as they move from one part of the
facility to another. Monitoring their movements requires
corrections officers to accurately identify individual prisoners
by sight as they pass through security posts. It also requires
frequent telephone and radio communications between officers
at two or more security posts, paper passes authorizing
inmates’ movements, and dry-erase or clip boards with
handwritten records to note when prisoners left one area
and entered another. Despite the best precautions and well-thought-out
practices, mistakes can be made, officers’ attention
can be diverted, and late-arriving inmates not noticed or
searched for promptly.
Late-arriving, out-of-place prisoners can cause problems
in correctional settings. If nothing else, it means that
prison staff do not know where a particular inmate is at
any given time. That prisoner may simply have stopped to
chat with friends. Or, more seriously, he or she may be
engaging in illegal activities. Assaults and even murders
have been committed by inmates as they moved from one part
of a prison or jail to another.
In an effort to improve how inmate movements are tracked
within prisons and jails, the National Institute of Justice
has been testing the use of biometrics at the U.S. Naval
Consolidated Brig in Charleston, South Carolina. The $1
million technology demonstration project is a joint effort
of NIJ, the U.S. Navy’s Space and Naval Warfare Systems
Center, the Charleston brig, and the U.S. Department of
Defense’s (DoD’s) Biometrics Management Office.
Biometrics has been used previously to track the movement
of staff, visitors, and prisoners in and out of correctional
facilities. It has also been used to account for staff members
in the event of a riot or other prison disturbance. This
project represents the first use of biometrics to track
prisoner movements within a prison or jail. It was designed
to employ computer-based methods of tracking inmates to
improve the efficiency of corrections specialists[1]
and brig officials and to demonstrate how advanced technology
can make corrections facilities safer.
WHAT IS BIOMETRICS?
The term “biometrics” refers to a variety
of methods to verify a person’s identity using physiological
or behavioral characteristics such as iris, retinal, and
facial recognition; hand and finger geometry; fingerprint
and voice identification; and dynamic signature. It has
the advantage of not requiring a person to remember a
user name, password, or series of numbers while confirming
that the person is who he or she claims to be. Practical
uses of biometrics include allowing persons access to
keyless cars, rooms, and buildings; to financial and other
personal accounts; and to the departure areas of airport
terminals. More broadly, it is used to prevent identity
theft, preserve the confidentiality of information, and
reduce fraud.
Biometric systems can use several different physical
and/or behavioral characteristics for identification and
verification. Some are more technologically and commercially
advanced than others. Determining which biometric method
to employ depends on how the system is to be used, the
level of accuracy and reliability required, and other
factors such as cost and speed. Biometric methods can
also vary significantly from one application to another
and even from one vendor to another.
Biometrics systems are usually deployed using a three-step
process. First, a camera, scanner, or other sensor takes
an image or picture. Second, that image is made into a
pattern called a biometric signature. For example, with
fingerprints the signature comprises minutia points along
a finger’s ridges, splits, and end lines. Voice
recognition involves patterns of cadence, pitch, and tone.
Hand and finger geometry measures physical characteristics
such as length and thickness.
Third, the biometric signature is converted into a template
using a mathematical algorithm. Templates contain biometric
and other data in the form of numbers that are either
embedded on a plastic card or stored in a database. Some
systems use a card that can be inserted in or held near
a scanner that feeds the information on the card into
a computer. Other systems do not require a card; they
simply scan the biometric data. In either system, the
computer compares the biometric signature captured by
the scanner with those already in its files to find the
correct or closest match.
NIJ and DoD began examining biometric techniques for
criminal justice purposes in 2000. As part of that effort,
NIJ and DoD identified the Charleston naval brig as a
demonstration site. The brig is a relatively small, well-managed
jail with approximately 400 mostly low-risk prisoners.
The Navy wanted to upgrade security at the brig and make
it more efficient. At the same time, the adjacent Space
and Naval Warfare Systems Center was available to help
develop the biometrics system and the computer software
necessary to run it.
Identifying Inmates
Called the Biometric Inmate Tracking System (BITS), the
project was implemented in phases that, together, transformed
the existing manual system into a computer-based system
and then into a biometric- and computer-based system. In
carrying out that transformation, project designers had
to find the biometric method that would work best at the
Charleston brig and then develop computer software capable
of identifying and verifying individual inmates based on
their biometric characteristics. The software also had to
be easy enough to operate so that corrections specialists
with limited prior training or experience on computers could
understand how to use it.[2]
All biometric methods—iris, facial, retinal, finger
and hand geometry, voice, and fingerprint—were tested
over a 3-year period. All had been developed, tested, and
used in other settings, mostly by commercial firms. And
all were found to have advantages and disadvantages at the
Charleston brig. Facial recognition produced too many false
positives on prisoners. Although biometric methods do not
have to work every time to be effective, corrections specialists
had to visually identify the prisoners too often, thus slowing
the process. Iris recognition was the most accurate method
tested at the Charleston brig, but it was similarly judged
too slow to work effectively in a jail setting. Voice recognition
proved to be the least accurate method tested.
In the end, the fingerprint recognition method, now used
in conjunction with hand geometry, was judged to work best
at the Charleston brig. It provided the most accurate and
reliable matches at about one-third the cost of iris, facial,
and retinal methods. The fingerprint method also moved prisoners
through the gates faster than the others. That’s a
prime consideration when, for example, corrections specialists
are moving 50 or more prisoners at once from housing or
work areas to the galley at mealtime. Fingerprint readers
were also easier to use and more durable than other readers.
Tracking Inmates
In the next phase, the manual dry-erase board and paper
system was replaced with a computerized tracking system
in which a server contained all data on inmate movements.
Brig staff could access the data from each housing unit,
the control center, and the enrollment area. Biometric scanners
were then added to further verify the location of prisoners.
As the system now works, the computer finds a biometric
match, identifies the individual prisoner, and confirms
that he or she is authorized to go from one part of the
brig to another. The computer also sends a message to the
next security post on the prisoner’s authorized path
that the prisoner is on his or her way. No escort or paper
record is necessary because the computer records all prisoner
movement between security posts at different parts of the
brig. If a prisoner fails to show up within a specified
time, usually 5 minutes, an alarm is sounded and the staff
are alerted that a prisoner is out of place.
Evaluating the Project
Almost from the beginning, outside experts were engaged
to help NIJ and the U.S. Navy evaluate how well the computer
tracking and biometrics systems worked, if they made the
Charleston brig safer, and whether they worked better than
the manual system they replaced. Initially, evaluators conducted
surveys of brig staff taken before the biometric system
was fully in place. The surveys showed that the corrections
specialists and other brig officials thought the existing
system for tracking prisoner movements worked fine most
of the time.
To test that assumption, evaluators asked brig officials
to “grab” and hold a prisoner who was authorized
to move from one part of the brig to another after that
prisoner had passed through the first security post. By
so doing, they deliberately caused a prisoner to be late
and out of place, thus creating a security breach. The results
showed that the Charleston brig’s manual system did
not work as well as its staff had thought.
Under the manual system of tracking inmate movements, the
corrections specialists failed to note a prisoner’s
nonarrival in all 12 test grabs. Under the manual system,
it took corrections specialists an average of 43 minutes
to notice an out-of-place prisoner. In half the cases, more
than 1 hour passed before the corrections specialists realized
the situation. Once the computer tracking system was introduced,
however, the average time it took for staff to notice a
nonarriving inmate dropped to 17 minutes. In only 1 of 10
cases did more than 1 hour pass.
At the same time, the computer tracking system improved
the efficiency of corrections specialists and other brig
officials. Most corrections specialists learned the new
system quickly, which, when mastered, calls for less reliance
on their memory of individual prisoners and provides automatic
warnings when prisoners are deemed out of place. The system
frees corrections specialists from handling paper passes,
allowing them to spend more time actually watching prisoners
in their area. And that translates into improved staff efficiency.
So, too, do the fewer outgoing telephone and radio calls
made by the corrections specialists to ensure that a prisoner
has actually arrived at the next post on time. Once again,
that means more time for staff to spend actually watching
prisoners.
Next Steps
NIJ and project staff plan to take what has been learned
at the Charleston naval brig and apply it to a larger, civilian
prison. The goal is to develop the technology, software,
and methods to use biometrics in any prison or jail in the
United States.
Challenges lie ahead: Technological developments continue
to change the relative merits of the different recognition
and verification methods. A civilian prison represents a
riskier, higher use setting than a military jail for biometrics
to work, so a different set of criteria will need to be
developed to evaluate which systems work best. For example,
equipment durability may be more important because of higher
volumes of use and because of the increased potential for
deliberate vandalism by inmates likely to damage equipment
designed to track their movements.
The Charleston brig test is not yet completed—final
evaluations of the full biometric and computer system remain
to be finished and analyzed. Yet project staff are optimistic
that with further testing and analysis, biometrics technology
can be used successfully in U.S. prisons and jails to identify
and track inmates.
NCJ 212263
Notes
- The military job classification “corrections specialist”
is comparable to the civilian “corrections officer.”
- The Biometric Inmate Tracking Software, InmateTrac,
is a Government Off-the-Shelf (GOTS) product that runs using
open source software that is available for free to the correctional
community. For software configuration and administration
requirements, please contact Michael Besco at Michael.Besco@navy.mil.
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