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Program Profile: Integrated Ballistics Identification System (IBIS)

Evidence Rating: Effective - One study Effective - One study

Date: This profile was posted on June 14, 2011

Program Summary

An automated ballistics imaging and analysis system that populates a computerized database of digital ballistic images of bullets and casings from crime guns. The system assists forensic experts in making identifications for investigations and trials. The program is rated Effective. There was an increase in cold hits after system implementation.

Program Description

Program Goals
The Integrated Ballistics Identification System (IBIS) was created to expedite the highly labor-intensive and time-consuming task of matching ballistics information in police investigations. In addition to matching evidence from an ongoing or current investigation, IBIS can be used to link ballistic information to prior investigations and to guns used in crimes—that is, firearms that have been used in the commission of multiple crimes but that may not have been recovered in the investigation.

Target Sites
This technology was built and designed for forensic identification of ballistic information to firearms and is appropriate to use in any police department’s evidence or forensic unit.

Program Theory and Activities

Ammunition used in firearms has two distinct parts: 1) the bullet or projectile that leaves the barrel of a gun and strikes the intended target and 2) the cartridge that contains the gunpowder and propellant used to drive the projectile. When the trigger of a firearm is squeezed, this engages the firing pin to strike the rear of the cartridge, which ignites the gunpowder and propellant contained within. This explosion pushes the tip of the ammunition—the bullet—forward, separating it from the cartridge and propelling it down the length of the barrel.


Every firearm leaves unique identifying characteristics on the bullet and the cartridge during the firing process. The barrel of every firearm leaves lands, grooves, and specific marks, from the rifling—the winding pattern inside a barrel that spins the bullet to improve accuracy—on the bullet. The firing pin leaves marks on the rear of the cartridge as it is struck, and the breech face leaves ejection marks on the side of the spent cartridge casing. These microscopic marks are similar to fingerprints. Just as no two sets of fingerprints are alike, no two firearms are the same. For example, two identical 9mm pistols will not produce identical markings on the bullet and the casing. Hence, the ballistic information produced from these two pistols can be used to determine which gun was used in a crime and ideally link it to the offender who used it.

Traditional methods of matching ballistics information involve firearm forensic experts taking evidence collected from a single crime scene and searching through image databases and other evidence collections manually to select potential candidates until they find an exact match. The IBIS assists in the manual searching and identifying of potential candidate matches by automating the entire system and searching evidence of multiple crime scenes simultaneously. With every new image entered, IBIS compares the recovered evidence with existing images from prior crime scenes to identify possible matches. IBIS is able to search through volumes of existing images and prior evidence from crime scenes and suggests a small number of cases as potential matches. A firearm forensic expert then examines each potential match and makes the final determination of whether a match actually exists. IBIS is similar to an Internet search engine, in that it is a tool used to cull through vast amounts of information and the user makes the ultimate decision whether the search engine has produced the correct results.

Additional Information

IBIS is the software behind the Bureau of Alcohol, Tobacco, Firearms, and Explosives’ and the Federal Bureau of Investigation’s National Integrated Ballistics Information Network (NIBIN). The NIBIN was implemented in 2000. Within 3 years, IBIS technology had been used in 222 sites across the country and was responsible for 6,500 bullet-to-firearm matches.

Evaluation Outcomes

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Study 1
Cold Case Hits

Regression results from the study by Braga and Pierce (2004) show a significant 6.23-fold increase in the monthly number of cold hits generated by the Boston Police Department’s Ballistics Unit after implementation of Integrated Ballistics Identification System (IBIS). This translates to 523 percent more cold hits per month. This analysis controlled for trends, seasonal variations, and the monthly number of crime guns entered into the system.
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Evaluation Methodology

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Study 1

Braga and Pierce (2004) examined the effectiveness of Integrated Ballistics Identification System (IBIS) in changing the Boston (Mass.) Police Department’s Ballistics Unit (BPD) productivity in linking gun crimes compared with the traditional matching of ballistics information by firearm examiners and forensic experts. This was done using a single group interrupted-time-series design. As such, there is no control or comparison group, just the intervention group. In this case it is essential to control for any other external forces that could affect the results of the single treatment group. During the 12-year study period, there were no significant changes in the level of staffing or the procedures and protocol used to identify ballistic evidence in the BPD. The only change was the implementation and use of IBIS, thus this study examines the effect of integrating IBIS into standard forensic investigations.


To determine the effectiveness of IBIS, the researchers compared, on the one hand, the number of ballistic matches and “cold hits” made by firearm forensic experts with the assistance of IBIS with, on the other hand, those made without the assistance of IBIS. Cold hits are matches to ballistics evidence recovered at other crime scenes to determine whether separate gun crimes were linked. BPD firearm forensic experts did not systematically compare ballistic evidence from new or fresh crime scene investigations with other crime scenes. Cold hits did occur, but not in a systematic fashion. Typically, cold hits came about when a firearms forensic expert noticed a distinguishing feature on a particular cartridge and recalled a similar image from another case or when detectives acquired information from confidential informants that two gun crimes might be linked.


Productivity was measured by the number of annual and monthly cold hits made by the BPD Ballistics Unit between 1990 and 2002. This timeframe was split into two periods; the pre–IBIS period from 1990 to 1994 and the post–IBIS period from 1995 to 2002. Negative binomial regression and Auto Regressive Integrated Moving Average models were used in the time-series analysis. These analytic techniques are needed, as the outcome variable in this study is a counting of events. Additionally, these techniques address issues inherent with count data (e.g., overdispersion) and time-series analyses (e.g., trend, seasonality, and random error).

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In 1995, the adoption of the Integrated Ballistics Identification System (IBIS) cost the Boston Police Department’s Ballistics Unit $540,000. The same equipment cost only $295,000 in 2003, because of the decreasing costs of technology in general.
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Evidence-Base (Studies Reviewed)

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These sources were used in the development of the program profile:

Study 1
Braga, Anthony A., and Glenn L. Pierce. 2004. “Linking Crime Guns: The Impact of Ballistics Imaging Technology on the Productivity of the Boston Police Department’s Ballistics Unit.” Journal of Forensic Science 49:1–6.
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Additional References

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These sources were used in the development of the program profile:

Nennstiel, Ruprecht, and Joachim Rahm. 2006a. “A Parameter Study Regarding the IBIS Correlator.” Journal of Forensic Science 51:18–23.

———. 2006b. “An Experience Report Regarding the Performance of the IBIS Correlator.” Journal of Forensic Science 51:24–30.
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Program Snapshot

Geography: Urban

Setting (Delivery): Other Community Setting, High Crime Neighborhoods/Hot Spots

Current Program Status: Active

Anthony Braga
Senior Research Fellow
Harvard University, John F. Kennedy School of Government
79 John F. Kennedy Street
Cambridge MA 02138
Phone: 617.495.5188