skip navigation

Add your conference to our Justice Events calendar


Register for Latest Research

Stay Informed
Register with NCJRS to receive NCJRS's biweekly e-newsletter JUSTINFO and additional periodic emails from NCJRS and the NCJRS federal sponsors that highlight the latest research published or sponsored by the Office of Justice Programs.

NCJRS Abstract

The document referenced below is part of the NCJRS Library collection. To conduct further searches of the collection, visit the NCJRS Abstracts Database. See the Obtain Documents page for direction on how to access resources online, via mail, through interlibrary loans, or in a local library.

  NCJ Number: NCJ 230162     Find in a Library
  Title: Quantification of Toolmarks, Final Technical Report
  Document URL: PDF 
  Author(s): L. S. Chumbley
  Date Published: 08/2009
  Page Count: 38
  Annotation: The goal of this research was to develop a methodology to characterize toolmarks using quantitative measures of the three-dimensional nature of the mark, rather than a two-dimensional image of the mark.
  Abstract: Results from this research suggest that it can be concluded that an objective method of toolmark comparison is feasible as a screening process, and that related contextual information should be included in this process in order to enhance findings. However, an experienced examiner is still essential in verifying the actual results of any computer-based algorithm. Once such a methodology was developed in which objective comparisons between two toolmarks could be made to determine whether marks made from similar tools could be distinguished quantitatively from marks made using other tools. The toolmarks studied were produced using 50 sequentially manufactured screwdriver tips that had not seen service. The algorithm developed to allow comparison of two scans in an objective, quantitative manner mimics the procedure used by forensic. Initial results showed that known matches, or marks made by the same screwdriver, could be identified on average 95 percent of the. In an effort to improve the result, a study involving actual examiners was conducted. In this study the examiners yielded a higher degree of success than the algorithm, however examiners are trained to only make a positive ID when absolutely certain whereas the algorithm is not as selective. Overall, this comparison revealed that contextual information plays a large role in the examiner’s decision-making process while such information was purposefully omitted from the initial trials of the algorithm in order to make its operation as general as possible. A final study including contextual information was conducted, and the results were vastly superior to those obtained when this information was omitted.
  Main Term(s): Police policies and procedures
  Index Term(s): Toolmark identification ; Evidence identification and analysis ; Forensics/Forensic Sciences ; Investigative techniques
  Sponsoring Agency: National Institute of Justice (NIJ)
US Department of Justice
Office of Justice Programs
United States of America
  Grant Number: 2004-R-IJ-088
  Sale Source: National Institute of Justice/NCJRS
Box 6000
Rockville, MD 20849
United States of America

NCJRS Photocopy Services
Box 6000
Rockville, MD 20849-6000
United States of America
  Type: Report (Study/Research)
  Country: United States of America
  Language: English
  To cite this abstract, use the following link:

*A link to the full-text document is provided whenever possible. For documents not available online, a link to the publisher's website is provided. Tell us how you use the NCJRS Library and Abstracts Database - send us your feedback.